The content of the window is blank.

This includes such popups as:

• The "What should Nightly do with this file?" dialog when initiating a download;
• The "Close tabs?" confirmation dialog when closing a window containing multiple tabs.

Subsequent popup windows during the session do not exhibit the problem, only the first one.

My about:support:

Application Basics
------------------

Name: Firefox
Version: 71.0a1
Build ID: 20191008093420
Update Channel: nightly
User Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:71.0) Gecko/20100101 Firefox/71.0
OS: Windows_NT 10.0
Launcher Process: Enabled
Multiprocess Windows: 7/7 Enabled by default
Remote Processes: 10
Enterprise Policies: Inactive
Google Location Service Key: Found
Google Safebrowsing Key: Found
Mozilla Location Service Key: Found
Safe Mode: false

Crash Reports for the Last 3 Days
---------------------------------

Nightly Features
----------------

Name: Firefox Screenshots
Version: 39.0.0
ID: screenshots@mozilla.org

Name: Form Autofill
Version: 1.0
ID: formautofill@mozilla.org

Name: Web Compat
Version: 6.2.0
ID: webcompat@mozilla.org

Name: WebCompat Reporter
Version: 1.1.0
ID: webcompat-reporter@mozilla.org

Remote Processes
----------------

Type: Web Content
Count: 8 / 8

Type: Extension
Count: 1

Type: GPU
Count: 1

Extensions
----------

Name: Amazon.co.uk
Version: 1.1
Enabled: true
ID: amazon@search.mozilla.org

Name: Bing
Version: 1.0
Enabled: true
ID: bing@search.mozilla.org

Name: DuckDuckGo
Version: 1.0
Enabled: true
ID: ddg@search.mozilla.org

Name: eBay
Version: 1.0
Enabled: true
ID: ebay@search.mozilla.org

Name: Facebook Container
Version: 2.0.3
Enabled: true
ID: @contain-facebook

Name: Gecko Profiler
Version: 0.30
Enabled: true
ID: geckoprofiler@mozilla.com

Name: Google
Version: 1.0
Enabled: true
ID: google@search.mozilla.org

Name: HTTPS Everywhere
Version: 2019.6.27
Enabled: true
ID: https-everywhere@eff.org

Name: In-Page Pop-up Reporter
Version: 1.6
Enabled: true
ID: {feb799e2-29e2-4e35-b862-cc4e1842b6f5}

Name: INXPO Speed Control
Version: 0.2
Enabled: true
ID: inxpo-speed-control@mikeconley.ca

Name: MyQOnly
Version: 0.7.1
Enabled: true
ID: myqonly@mikeconley.ca

Name: Twitter
Version: 1.0
Enabled: true
ID: twitter@search.mozilla.org

Name: uBlock Origin
Version: 1.22.4
Enabled: true
ID: uBlock0@raymondhill.net

Name: Wikipedia (en)
Version: 1.0
Enabled: true
ID: wikipedia@search.mozilla.org

Name: KeePassXC-Browser
Version: 1.5.1
Enabled: false
ID: keepassxc-browser@keepassxc.org

Security Software
-----------------

Type: Windows Defender Antivirus

Type:

Type: Windows Firewall

Graphics
--------

Features
Compositing: Direct3D 11 (Advanced Layers)
Asynchronous Pan/Zoom: wheel input enabled; scrollbar drag enabled; keyboard enabled; autoscroll enabled
WebGL 1 Driver WSI Info: EGL_VENDOR: Google Inc. (adapter LUID: 0000000000017876) EGL_VERSION: 1.4 (ANGLE 2.1.0.21dccd386996) EGL_EXTENSIONS: EGL_EXT_create_context_robustness EGL_ANGLE_d3d_share_handle_client_buffer EGL_ANGLE_d3d_texture_client_buffer EGL_ANGLE_surface_d3d_texture_2d_share_handle EGL_ANGLE_query_surface_pointer EGL_ANGLE_window_fixed_size EGL_ANGLE_keyed_mutex EGL_ANGLE_surface_orientation EGL_ANGLE_direct_composition EGL_NV_post_sub_buffer EGL_KHR_create_context EGL_EXT_device_query EGL_KHR_image EGL_KHR_image_base EGL_KHR_gl_texture_2D_image EGL_KHR_gl_texture_cubemap_image EGL_KHR_gl_renderbuffer_image EGL_KHR_get_all_proc_addresses EGL_KHR_stream EGL_KHR_stream_consumer_gltexture EGL_NV_stream_consumer_gltexture_yuv EGL_ANGLE_flexible_surface_compatibility EGL_ANGLE_stream_producer_d3d_texture EGL_ANGLE_create_context_webgl_compatibility EGL_CHROMIUM_create_context_bind_generates_resource EGL_CHROMIUM_sync_control EGL_EXT_pixel_format_float EGL_KHR_surfaceless_context EGL_ANGLE_display_texture_share_group EGL_ANGLE_create_context_client_arrays EGL_ANGLE_program_cache_control EGL_ANGLE_robust_resource_initialization EGL_ANGLE_create_context_extensions_enabled EGL_ANDROID_blob_cache EGL_ANDROID_recordable EGL_EXTENSIONS(nullptr): EGL_EXT_client_extensions EGL_EXT_platform_base EGL_EXT_platform_device EGL_ANGLE_platform_angle EGL_ANGLE_platform_angle_d3d EGL_ANGLE_device_creation EGL_ANGLE_device_creation_d3d11 EGL_ANGLE_experimental_present_path EGL_KHR_client_get_all_proc_addresses EGL_KHR_debug EGL_ANGLE_explicit_context
WebGL 1 Driver Renderer: Google Inc. -- ANGLE (NVIDIA Quadro P500 Direct3D11 vs_5_0 ps_5_0)
WebGL 1 Driver Version: OpenGL ES 2.0 (ANGLE 2.1.0.21dccd386996)
WebGL 1 Driver Extensions: GL_ANGLE_client_arrays GL_ANGLE_depth_texture GL_ANGLE_explicit_context GL_ANGLE_explicit_context_gles1 GL_ANGLE_framebuffer_blit GL_ANGLE_framebuffer_multisample GL_ANGLE_instanced_arrays GL_ANGLE_lossy_etc_decode GL_ANGLE_memory_size GL_ANGLE_multi_draw GL_ANGLE_multiview_multisample GL_ANGLE_pack_reverse_row_order GL_ANGLE_program_cache_control GL_ANGLE_provoking_vertex GL_ANGLE_request_extension GL_ANGLE_robust_client_memory GL_ANGLE_texture_compression_dxt3 GL_ANGLE_texture_compression_dxt5 GL_ANGLE_texture_usage GL_ANGLE_translated_shader_source GL_CHROMIUM_bind_generates_resource GL_CHROMIUM_bind_uniform_location GL_CHROMIUM_color_buffer_float_rgb GL_CHROMIUM_color_buffer_float_rgba GL_CHROMIUM_copy_compressed_texture GL_CHROMIUM_copy_texture GL_CHROMIUM_sync_query GL_EXT_blend_func_extended GL_EXT_blend_minmax GL_EXT_color_buffer_half_float GL_EXT_debug_marker GL_EXT_discard_framebuffer GL_EXT_disjoint_timer_query GL_EXT_draw_buffers GL_EXT_float_blend GL_EXT_frag_depth GL_EXT_instanced_arrays GL_EXT_map_buffer_range GL_EXT_occlusion_query_boolean GL_EXT_read_format_bgra GL_EXT_robustness GL_EXT_sRGB GL_EXT_shader_texture_lod GL_EXT_texture_compression_bptc GL_EXT_texture_compression_dxt1 GL_EXT_texture_compression_s3tc_srgb GL_EXT_texture_filter_anisotropic GL_EXT_texture_format_BGRA8888 GL_EXT_texture_rg GL_EXT_texture_storage GL_EXT_unpack_subimage GL_KHR_debug GL_KHR_parallel_shader_compile GL_KHR_robust_buffer_access_behavior GL_NV_EGL_stream_consumer_external GL_NV_fence GL_NV_pack_subimage GL_NV_pixel_buffer_object GL_OES_EGL_image GL_OES_EGL_image_external GL_OES_compressed_ETC1_RGB8_texture GL_OES_depth32 GL_OES_element_index_uint GL_OES_get_program_binary GL_OES_mapbuffer GL_OES_packed_depth_stencil GL_OES_rgb8_rgba8 GL_OES_standard_derivatives GL_OES_surfaceless_context GL_OES_texture_border_clamp GL_OES_texture_float GL_OES_texture_float_linear GL_OES_texture_half_float GL_OES_texture_half_float_linear GL_OES_texture_npot GL_OES_vertex_array_object OES_compressed_EAC_R11_signed_texture OES_compressed_EAC_R11_unsigned_texture OES_compressed_EAC_RG11_signed_texture OES_compressed_EAC_RG11_unsigned_texture OES_compressed_ETC2_RGB8_texture OES_compressed_ETC2_RGBA8_texture OES_compressed_ETC2_punchthroughA_RGBA8_texture OES_compressed_ETC2_punchthroughA_sRGB8_alpha_texture OES_compressed_ETC2_sRGB8_alpha8_texture OES_compressed_ETC2_sRGB8_texture
WebGL 1 Extensions: ANGLE_instanced_arrays EXT_blend_minmax EXT_color_buffer_half_float EXT_disjoint_timer_query EXT_float_blend EXT_frag_depth EXT_shader_texture_lod EXT_sRGB EXT_texture_compression_bptc EXT_texture_filter_anisotropic OES_element_index_uint OES_standard_derivatives OES_texture_float OES_texture_float_linear OES_texture_half_float OES_texture_half_float_linear OES_vertex_array_object WEBGL_color_buffer_float WEBGL_compressed_texture_s3tc WEBGL_compressed_texture_s3tc_srgb WEBGL_debug_renderer_info WEBGL_debug_shaders WEBGL_depth_texture WEBGL_draw_buffers WEBGL_lose_context
WebGL 2 Driver WSI Info: EGL_VENDOR: Google Inc. (adapter LUID: 0000000000017876) EGL_VERSION: 1.4 (ANGLE 2.1.0.21dccd386996) EGL_EXTENSIONS: EGL_EXT_create_context_robustness EGL_ANGLE_d3d_share_handle_client_buffer EGL_ANGLE_d3d_texture_client_buffer EGL_ANGLE_surface_d3d_texture_2d_share_handle EGL_ANGLE_query_surface_pointer EGL_ANGLE_window_fixed_size EGL_ANGLE_keyed_mutex EGL_ANGLE_surface_orientation EGL_ANGLE_direct_composition EGL_NV_post_sub_buffer EGL_KHR_create_context EGL_EXT_device_query EGL_KHR_image EGL_KHR_image_base EGL_KHR_gl_texture_2D_image EGL_KHR_gl_texture_cubemap_image EGL_KHR_gl_renderbuffer_image EGL_KHR_get_all_proc_addresses EGL_KHR_stream EGL_KHR_stream_consumer_gltexture EGL_NV_stream_consumer_gltexture_yuv EGL_ANGLE_flexible_surface_compatibility EGL_ANGLE_stream_producer_d3d_texture EGL_ANGLE_create_context_webgl_compatibility EGL_CHROMIUM_create_context_bind_generates_resource EGL_CHROMIUM_sync_control EGL_EXT_pixel_format_float EGL_KHR_surfaceless_context EGL_ANGLE_display_texture_share_group EGL_ANGLE_create_context_client_arrays EGL_ANGLE_program_cache_control EGL_ANGLE_robust_resource_initialization EGL_ANGLE_create_context_extensions_enabled EGL_ANDROID_blob_cache EGL_ANDROID_recordable EGL_EXTENSIONS(nullptr): EGL_EXT_client_extensions EGL_EXT_platform_base EGL_EXT_platform_device EGL_ANGLE_platform_angle EGL_ANGLE_platform_angle_d3d EGL_ANGLE_device_creation EGL_ANGLE_device_creation_d3d11 EGL_ANGLE_experimental_present_path EGL_KHR_client_get_all_proc_addresses EGL_KHR_debug EGL_ANGLE_explicit_context
WebGL 2 Driver Renderer: Google Inc. -- ANGLE (NVIDIA Quadro P500 Direct3D11 vs_5_0 ps_5_0)
WebGL 2 Driver Version: OpenGL ES 3.0 (ANGLE 2.1.0.21dccd386996)
WebGL 2 Driver Extensions: GL_ANGLE_client_arrays GL_ANGLE_copy_texture_3d GL_ANGLE_depth_texture GL_ANGLE_explicit_context GL_ANGLE_explicit_context_gles1 GL_ANGLE_framebuffer_blit GL_ANGLE_framebuffer_multisample GL_ANGLE_instanced_arrays GL_ANGLE_lossy_etc_decode GL_ANGLE_memory_size GL_ANGLE_multi_draw GL_ANGLE_multiview_multisample GL_ANGLE_pack_reverse_row_order GL_ANGLE_program_cache_control GL_ANGLE_provoking_vertex GL_ANGLE_request_extension GL_ANGLE_robust_client_memory GL_ANGLE_texture_compression_dxt3 GL_ANGLE_texture_compression_dxt5 GL_ANGLE_texture_multisample GL_ANGLE_texture_usage GL_ANGLE_translated_shader_source GL_CHROMIUM_bind_generates_resource GL_CHROMIUM_bind_uniform_location GL_CHROMIUM_color_buffer_float_rgb GL_CHROMIUM_color_buffer_float_rgba GL_CHROMIUM_copy_compressed_texture GL_CHROMIUM_copy_texture GL_CHROMIUM_sync_query GL_EXT_blend_func_extended GL_EXT_blend_minmax GL_EXT_color_buffer_float GL_EXT_color_buffer_half_float GL_EXT_debug_marker GL_EXT_discard_framebuffer GL_EXT_disjoint_timer_query GL_EXT_draw_buffers GL_EXT_float_blend GL_EXT_frag_depth GL_EXT_instanced_arrays GL_EXT_map_buffer_range GL_EXT_occlusion_query_boolean GL_EXT_read_format_bgra GL_EXT_robustness GL_EXT_sRGB GL_EXT_shader_texture_lod GL_EXT_texture_compression_bptc GL_EXT_texture_compression_dxt1 GL_EXT_texture_compression_s3tc_srgb GL_EXT_texture_filter_anisotropic GL_EXT_texture_format_BGRA8888 GL_EXT_texture_norm16 GL_EXT_texture_rg GL_EXT_texture_storage GL_EXT_unpack_subimage GL_KHR_debug GL_KHR_parallel_shader_compile GL_KHR_robust_buffer_access_behavior GL_NV_EGL_stream_consumer_external GL_NV_fence GL_NV_pack_subimage GL_NV_pixel_buffer_object GL_OES_EGL_image GL_OES_EGL_image_external GL_OES_EGL_image_external_essl3 GL_OES_compressed_ETC1_RGB8_texture GL_OES_depth32 GL_OES_element_index_uint GL_OES_get_program_binary GL_OES_mapbuffer GL_OES_packed_depth_stencil GL_OES_rgb8_rgba8 GL_OES_standard_derivatives GL_OES_surfaceless_context GL_OES_texture_border_clamp GL_OES_texture_float GL_OES_texture_float_linear GL_OES_texture_half_float GL_OES_texture_half_float_linear GL_OES_texture_npot GL_OES_vertex_array_object GL_OVR_multiview2 OES_compressed_EAC_R11_signed_texture OES_compressed_EAC_R11_unsigned_texture OES_compressed_EAC_RG11_signed_texture OES_compressed_EAC_RG11_unsigned_texture OES_compressed_ETC2_RGB8_texture OES_compressed_ETC2_RGBA8_texture OES_compressed_ETC2_punchthroughA_RGBA8_texture OES_compressed_ETC2_punchthroughA_sRGB8_alpha_texture OES_compressed_ETC2_sRGB8_alpha8_texture OES_compressed_ETC2_sRGB8_texture
WebGL 2 Extensions: EXT_color_buffer_float EXT_disjoint_timer_query EXT_float_blend EXT_texture_compression_bptc EXT_texture_filter_anisotropic OES_texture_float_linear OVR_multiview2 WEBGL_compressed_texture_s3tc WEBGL_compressed_texture_s3tc_srgb WEBGL_debug_renderer_info WEBGL_debug_shaders WEBGL_lose_context
Direct2D: true
Off Main Thread Painting Enabled: true
Off Main Thread Painting Worker Count: 4
Target Frame Rate: 60
DirectWrite: true (10.0.18362.356)
GPU #1
Active: Yes
Description: NVIDIA Quadro P500
Vendor ID: 0x10de
Device ID: 0x1d33
Driver Version: 23.21.13.9125
Driver Date: 3-16-2018
Drivers: C:\WINDOWS\System32\DriverStore\FileRepository\nvlt.inf_amd64_97992900c592012e\nvldumdx.dll,C:\WINDOWS\System32\DriverStore\FileRepository\nvlt.inf_amd64_97992900c592012e\nvldumdx.dll,C:\WINDOWS\System32\DriverStore\FileRepository\nvlt.inf_amd64_97992900c592012e\nvldumdx.dll,C:\WINDOWS\System32\DriverStore\FileRepository\nvlt.inf_amd64_97992900c592012e\nvldumdx.dll C:\WINDOWS\System32\DriverStore\FileRepository\nvlt.inf_amd64_97992900c592012e\nvldumd.dll,C:\WINDOWS\System32\DriverStore\FileRepository\nvlt.inf_amd64_97992900c592012e\nvldumd.dll,C:\WINDOWS\System32\DriverStore\FileRepository\nvlt.inf_amd64_97992900c592012e\nvldumd.dll,C:\WINDOWS\System32\DriverStore\FileRepository\nvlt.inf_amd64_97992900c592012e\nvldumd.dll
Subsys ID: 225b17aa
RAM: 2048
GPU #2
Active: No
Description: Intel(R) UHD Graphics 620
Vendor ID: 0x8086
Device ID: 0x5917
Driver Version: 26.20.100.6951
Driver Date: 6-12-2019
Drivers: igdumdim64 igd10iumd64 igd10iumd64 igd12umd64 igdumdim32 igd10iumd32 igd10iumd32 igd12umd32
Subsys ID: 225b17aa
RAM: Unknown
Diagnostics
AzureCanvasBackend: direct2d 1.1
AzureCanvasBackend (UI Process): skia
AzureContentBackend: direct2d 1.1
AzureContentBackend (UI Process): skia
AzureFallbackCanvasBackend (UI Process): none
CMSOutputProfile: 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Display0: 3840x2160@60Hz
Display1: 1920x1200@59Hz
Display2: 1920x1200@59Hz
DisplayCount: 3
GPUProcessPid: 2792
GPUProcess: Terminate GPU Process
Device Reset: Trigger Device Reset
ClearType Parameters: \\.\DISPLAY1 [ Gamma: 1.8 Pixel Structure: RGB ClearType Level: 100 Enhanced Contrast: 50 ] \\.\DISPLAY2 [ Gamma: 1.8 Pixel Structure: RGB ClearType Level: 100 Enhanced Contrast: 50 ] \\.\DISPLAY3 [ Gamma: 1.8 Pixel Structure: RGB ClearType Level: 100 Enhanced Contrast: 50 ]
Decision Log
WEBRENDER:
opt-in by default: WebRender is an opt-in feature
WEBRENDER_QUALIFIED:
blocked-has-battery by env: Has battery




Media
-----

Audio Backend: wasapi
Max Channels: 2
Preferred Sample Rate: 48000
Output Devices
Name: Group
Headphones (ThinkPad Dock USB Audio): USB\VID_17EF&PID_306F&MI_00\b&21f71a7c&0&0000
DELL U2410 (Intel(R) Display Audio): HDAUDIO\FUNC_01&VEN_8086&DEV_280B&SUBSYS_80860101&REV_1000\4&1e912a37&0&0201
:
DELL U2410 (Intel(R) Display Audio): HDAUDIO\FUNC_01&VEN_8086&DEV_280B&SUBSYS_80860101&REV_1000\4&1e912a37&0&0201
Headphones (ThinkPad Dock USB Audio): USB\VID_17EF&PID_306F&MI_00\b&21f71a7c&0&0000
Speaker/HP (Realtek High Definition Audio): HDAUDIO\FUNC_01&VEN_10EC&DEV_0257&SUBSYS_17AA225A&REV_1000\4&1e912a37&0&0001
Speakers (Plantronics .Audio 655 DSP): USB\VID_047F&PID_C008&MI_00\d&19b8261c&0&0000
DELL U2410 (Intel(R) Display Audio): HDAUDIO\FUNC_01&VEN_8086&DEV_280B&SUBSYS_80860101&REV_1000\4&1e912a37&0&0201
Input Devices
Name: Group
:
Microphone (ThinkPad Dock USB Audio): USB\VID_17EF&PID_306F&MI_00\b&21f71a7c&0&0000
Microphone (ThinkPad Dock USB Audio): USB\VID_17EF&PID_306F&MI_00\b&21f71a7c&0&0000
Microphone (Plantronics .Audio 655 DSP): USB\VID_047F&PID_C008&MI_00\d&19b8261c&0&0000
Microphone Array (Realtek High Definition Audio): HDAUDIO\FUNC_01&VEN_10EC&DEV_0257&SUBSYS_17AA225A&REV_1000\4&1e912a37&0&0001
Microphone (Plantronics .Audio 655 DSP): USB\VID_047F&PID_C008&MI_00\d&19b8261c&0&0000
Microphone (Logitech Webcam C930e): USB\VID_046D&PID_0843&MI_02\d&e659c09&0&0002
Media Capabilities
Enumerate database

Important Modified Preferences
------------------------------

accessibility.force_disabled: 1
accessibility.indicator.enabled: true
accessibility.typeaheadfind.flashBar: 0
browser.cache.disk.amount_written: 515043
browser.cache.disk.capacity: 1048576
browser.cache.disk.filesystem_reported: 1
browser.cache.disk.hashstats_reported: 1
browser.cache.disk.smart_size.first_run: false
browser.cache.disk.telemetry_report_ID: 30
browser.cache.frecency_experiment: 1
browser.places.smartBookmarksVersion: 8
browser.search.suggest.enabled: false
browser.search.useDBForOrder: true
browser.sessionstore.upgradeBackup.latestBuildID: 20191008093420
browser.startup.homepage_override.buildID: 20191008093420
browser.startup.homepage_override.mstone: 71.0a1
browser.tabs.firstWindowRestore.numPinnedTabs: 3
browser.urlbar.matchBuckets: general:5,suggestion:Infinity
browser.urlbar.placeholderName: Google
browser.urlbar.timesBeforeHidingSuggestionsHint: 2
dom.forms.autocomplete.formautofill: true
dom.max_chrome_script_run_time: 0
dom.push.userAgentID: 2140fecd47a740e99475f344fa30bad0
extensions.formautofill.addresses.enabled: false
extensions.formautofill.creditCards.enabled: false
extensions.lastAppVersion: 71.0a1
font.internaluseonly.changed: false
gfx.crash-guard.status.wmfvpxvideo: 2
gfx.crash-guard.wmfvpxvideo.appVersion: 71.0a1
gfx.crash-guard.wmfvpxvideo.deviceID: 0x1d33
gfx.crash-guard.wmfvpxvideo.driverVersion: 23.21.13.9125
idle.lastDailyNotification: 1570493296
javascript.options.asyncstack: false
layers.mlgpu.sanity-test-failed: false
media.benchmark.vp9.fps: 268
media.benchmark.vp9.versioncheck: 5
media.gmp-gmpopenh264.abi: x86_64-msvc-x64
media.gmp-gmpopenh264.lastUpdate: 1552797541
media.gmp-gmpopenh264.version: 1.8.1
media.gmp-manager.buildID: 20191008093420
media.gmp-manager.lastCheck: 1570566354
media.gmp-widevinecdm.abi: x86_64-msvc-x64
media.gmp-widevinecdm.lastUpdate: 1564377339
media.gmp-widevinecdm.version: 4.10.1440.19
media.gmp.storage.version.observed: 1
media.hardware-video-decoding.failed: false
network.cookie.prefsMigrated: true
network.dns.disablePrefetch: true
network.http.speculative-parallel-limit: 0
network.predictor.cleaned-up: true
network.predictor.enabled: false
network.prefetch-next: false
places.database.lastMaintenance: 1570314720
places.history.expiration.transient_current_max_pages: 144036
plugin.disable_full_page_plugin_for_types: application/pdf
privacy.donottrackheader.enabled: true
privacy.sanitize.pending: [{"id":"newtab-container","itemsToClear":[],"options":{}}]
privacy.socialtracking.notification.counter: 1
privacy.socialtracking.notification.enabled: false
privacy.socialtracking.notification.lastShown: 1565808613484
privacy.userContext.extension: @contain-facebook
security.remote_settings.crlite_filters.checked: 1569857970
security.remote_settings.intermediates.checked: 1569857970
security.sandbox.content.tempDirSuffix: {3e136edd-677b-446d-bf1f-3de2e1eebab4}
security.sandbox.plugin.tempDirSuffix: {9c1543ae-d0f5-4a24-bf31-a4baab119184}
security.tls.version.enable-deprecated: true
services.sync.declinedEngines: passwords,adblockplus
services.sync.engine.addresses.available: true
services.sync.engine.bookmarks.validation.lastTime: 1570573123
services.sync.engine.passwords: false
services.sync.engine.prefs.modified: false
services.sync.lastPing: 1570573121
services.sync.lastSync: Tue Oct 08 2019 16:18:43 GMT-0600 (Mountain Daylight Time)
signon.importedFromSqlite: true
signon.rememberSignons: false
storage.vacuum.last.index: 0
storage.vacuum.last.places.sqlite: 1567809369
ui.osk.debug.keyboardDisplayReason: IKPOS: Touch screen not found.

Important Locked Preferences
----------------------------

Places Database
---------------

JavaScript
----------

Incremental GC: true

Accessibility
-------------

Activated: false
Prevent Accessibility: 1
Accessible Handler Used: true
Accessibility Instantiator:

Library Versions
----------------

NSPR
Expected minimum version: 4.23 Beta
Version in use: 4.23 Beta

NSS
Expected minimum version: 3.47 Beta
Version in use: 3.47 Beta

NSSSMIME
Expected minimum version: 3.47 Beta
Version in use: 3.47 Beta

NSSSSL
Expected minimum version: 3.47 Beta
Version in use: 3.47 Beta

NSSUTIL
Expected minimum version: 3.47 Beta
Version in use: 3.47 Beta

Sandbox
-------

Content Process Sandbox Level: 5
Effective Content Process Sandbox Level: 5

Internationalization & Localization
-----------------------------------

Application Settings
Requested Locales: ["en-US"]
Available Locales: ["en-US"]
App Locales: ["en-US"]
Regional Preferences: ["en-US"]
Default Locale: "en-US"
Operating System
System Locales: ["en-US"]
Regional Preferences: ["en-US"]

It might be dup of Bug 1573710.

:aklotz, can you check if the problem is addressed on latest nightly?

I haven't been able to reproduce the problem in a while.

Good :) Thank you.