I know, sounds stupid, but it is what it is. It happens rarely, only with Firefox on the secondary display from my laptop, via HDMI. It starts with some random few thin horizontal bars across the window itself, and soon, it turns off my display. It seems the bigger the window is, the more severe the issues. So full screen usually, it shuts it off and keeps it off. Not black screen, no signal style. I manage to get it out by Winkey+arrow. If i then put it back same issue. If i lower the width of it, it manages to stay coherent longer, but still resets the display with a quick black screen on page reload. The lower bounds on a 1920x1080 display resolution was 1515 pixels. At 1515 pixels, it works fine, once this is triggered, it's very repeatable on 60-70% of webpages. If i drag another window on top of Firefox, the monitor comes back up. Before anyone asks: I have tried turning off hardware acceleration. I have tried putting firefox.exe to run on the integrated video card and on the dedicated 1060 Max Q videocard. I have cleared cache and etc. This persists on a Windows session, across multiple Firefox restarts. A computer restart technically fixes it but i have no clue what triggers it. Laptop monitor works fine.