User Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:85.0) Gecko/20100101 Firefox/85.0
Steps to reproduce:
Watching YouTube while doing something else GPU heavy like playing a game.
Memory usage kept increasing until other applications on my computer started to crash. Firefox was then using over 10Gb of memory
Firefox should stay way below 10Gb of memory usage.
It solved itself when closing that tab and opening a new one. Also probably a duplicate of 1679719