I've had the issue on multiple phones. Firefox nightly seemed to fix it for a while but it suffers from it too after a while. I need to test if it's UBO or the sister comment that says closing tabs and restarting helps. It's only on certain sites I really notice it, maybe JS or video heavy sites. NYTimes in particular.
Native Firefox on native Android (or at least the Samsung variant) here and I haven't had issues either.
I've had the issue on multiple phones. Firefox nightly seemed to fix it for a while but it suffers from it too after a while. I need to test if it's UBO or the sister comment that says closing tabs and restarting helps. It's only on certain sites I really notice it, maybe JS or video heavy sites. NYTimes in particular.