Environment:
Browser / Version: Firefox Nightly 92.0a1 (🦎 92.0a1-20210730093652)
Operating System: Google Pixel 5 (Android 11) - 1080 x 2340 pixels, 19.5:9 ratio (~432 ppi density), Samsung Galaxy S8 (Android 9) - 1440 x 2960 pixels, 18.5:9 ratio (~570 ppi density)

Prerequisites:
ETP - Strict enabled.

Steps to reproduce:

1. Navigate to https://www.mapillary.com/app/reset_password?nonce=Dwd4zIPVWGZ7swcVWM9MQurP3yDHTDRT&email=artfaber%40gmail.com
2. Observe the page.

Expected Behavior:
The page loads, displaying the "Reset password" page.

Actual Behavior:
The page doesn't load.

Notes:

1. Screenshot attached.
2. The issue is not reproducible with ETP - Standard.

I see they are hosting a bunch of scripts on Facebook CDNs, which are being blocked in strict mode:

The resource at “https://scontent-yyz1-1.xx.fbcdn.net/v/t39.38313-6/226038446_521110905823329_102289262391812146_n.js/runtime.d395d2b7aa76c3318463.js?_nc_cat=109&ccb=1-3&_nc_sid=43ad3e&_nc_ohc=TtFwKyToVkYAX-tjG2M&_nc_ht=scontent-yyz1-1.xx&oh=8d9cd5e866084903161189b2e0665e78&oe=610DA3E2” was blocked because content blocking is enabled.
The resource at “https://scontent-yyz1-1.xx.fbcdn.net/v/t39.38313-6/227436121_119380167086340_4509325621687827961_n.js/polyfills.6cc4a8b534c15faf0e33.js?_nc_cat=100&ccb=1-3&_nc_sid=43ad3e&_nc_ohc=u7fGX4gKBLYAX9sdf-x&_nc_ht=scontent-yyz1-1.xx&oh=f0a0c4ec17911de0122f8d830c1c3c7e&oe=610EA150” was blocked because content blocking is enabled.
The resource at “https://scontent-yyz1-1.xx.fbcdn.net/v/t39.38313-6/232412290_175306024547267_4111426941260037063_n.js/main.8fd419f53a2fc354831b.js?_nc_cat=104&ccb=1-3&_nc_sid=43ad3e&_nc_ohc=ipG_thUbwiIAX_MPMfl&_nc_ht=scontent-yyz1-1.xx&oh=89956a846a1425849a009c85d004d1c7&oe=610E5CA0” was blocked because content blocking is enabled.
The resource at “https://scontent-yyz1-1.xx.fbcdn.net/v/t39.38313-6/230488479_419254529393371_7728060983177090934_n.svg/mapillary-loading-logo.7abeb2d22bc68f4f4df1.svg?_nc_cat=111&ccb=1-3&_nc_sid=43ad3e&_nc_ohc=HGReK2wopKoAX8vKo-7&_nc_ht=scontent-yyz1-1.xx&oh=0e702a3a6ed7995e3624e96d61a3498b&oe=610ED1FA” was blocked because content blocking is enabled.
The resource at “https://scontent-yyz1-1.xx.fbcdn.net/v/t39.38313-6/228818392_152925716918725_3284419658272399997_n.woff/source-sans-pro-v14-latin-ext_latin-regular.c29659f8f842f4db84fc.woff?_nc_cat=108&ccb=1-3&_nc_sid=43ad3e&_nc_ohc=nsNedDC_9L0AX_8Lb-e&_nc_ht=scontent-yyz1-1.xx&oh=7cb8174cd87466026e0b86a0cc97488a&oe=610DAE49” was blocked because content blocking is enabled.
The resource at “https://scontent-yyz1-1.xx.fbcdn.net/v/t39.38313-6/227349753_577094597007801_2472914333811795770_n.ico/favicon.ico?_nc_cat=103&ccb=1-3&_nc_sid=43ad3e&_nc_ohc=JMon6-h-mNcAX_JFGhM&_nc_ht=scontent-yyz1-1.xx&oh=18f0a1df1474cb45438df65b4c95a840&oe=610F3A1D” was blocked because content blocking is enabled.
The resource at “https://scontent-yyz1-1.xx.fbcdn.net/v/t39.38313-6/228818392_152925716918725_3284419658272399997_n.woff/source-sans-pro-v14-latin-ext_latin-regular.c29659f8f842f4db84fc.woff?_nc_cat=108&ccb=1-3&_nc_sid=43ad3e&_nc_ohc=nsNedDC_9L0AX_8Lb-e&_nc_ht=scontent-yyz1-1.xx&oh=7cb8174cd87466026e0b86a0cc97488a&oe=610DAE49” was blocked because content blocking is enabled.

We would need to find a way to let users opt into allowing these.

Changing severity to S3 because this is a social tracking protection issue.