PiP/Picture-In-Picture Freezes the Whole Browser
Recently, whenever I put a video in PiP, the whole browser freezes. I'm not sure what causes it. The PiP player itself is playing and working fine, it's the browser as a whole that freezes completely. I can play/pause and even pop it back to its tab, but when I do, the browser is inaccessible to me because it freezes, despite the video still playing normally. I can only terminate the browser with Task Manager, otherwise the video will continue playing and the Firefox process goes on the background.
I have tried Googling for a way to fix it, but nothing seems to work. Some of the recommendations were to turn Hardware Acceleration off, allow autoplay, upgrade GPU drivers, and test in Troubleshoot Mode. I have autoplay completely off (including in about:config) and gave an exception to YouTube. I don't think this is the problem though, because I've had it set up this way for a long time, and the browser freezing only started happening recently. I have had Hardware Acceleration off for a while too, so it's not because of that. My GPU drivers are up-to-date (Nvidia). The browser still freezes in Troubleshoot Mode.
The problem is not limited to YouTube. Wherever I can pop the player off with PiP, it will freeze the whole browser (like Twitch or any other site with video player capabilities). I tried playing a video in a different browser and it worked just fine with no freezing, it only happens in Firefox.
I noticed that the common issue people report is the PiP player itself freezing, but my case is the exact opposite. The PiP plays fine while the rest of the browser freezes. I really like this feature and don't want to turn it off if possible. I like to pop the video out and watch it play while I scroll around on my desktop.