I've been seeing this since I got my new windows machine and started using windows on a regular basis. No STR, but may be tied to letting the browser run for more than a day without restarting. Restart clears it up, but once it comes back its back until the next restart

graphic section of about:support Adapter Description NVIDIA GeForce GTX 950 Adapter Drivers nvd3dumx,nvwgf2umx,nvwgf2umx,nvwgf2umx nvd3dum,nvwgf2um,nvwgf2um,nvwgf2um Adapter RAM 2048 Asynchronous Pan/Zoom wheel input enabled ClearType Parameters Gamma: 2200 Pixel Structure: R ClearType Level: 50 Enhanced Contrast: 50 Device ID 0x1402 Direct2D Enabled true DirectWrite Enabled true (10.0.10240.16430) Driver Date 9-13-2015 Driver Version 10.18.13.5598 GPU #2 Active false GPU Accelerated Windows 2/3 Basic Subsys ID 137619da Supports Hardware H264 Decoding No; Unsupported layers backend Vendor ID 0x10de WebGL Renderer Google Inc. -- ANGLE (NVIDIA GeForce GTX 950 Direct3D11 vs_5_0 ps_5_0) windowLayerManagerRemote false AzureCanvasBackend direct2d 1.1 AzureContentBackend direct2d 1.1 AzureFallbackCanvasBackend cairo AzureSkiaAccelerated 0