Sometimes I cannot close tabs by clicking the X, or refresh/go-forward/go-back using the buttons next to the address bar.
Computer B:
Sometimes I get downloads that have "Unknown time left" (0 bytes/sec) when the X of X KB/MB is 100% and you can't remove it from the downloads dropdown.
I just discovered a new bug on Computer B, clicking the hamburger menu doesn't do anything.
Both are Ubuntu.
(I'm not a fan of the new menu in Firefox Beta for Android. I guess it looks nicer due to the greater whitespace, it just break muscle memory and has less options/selections.)
I wonder, if these problems aren't Ubuntu fault, since it forces snap version of Firefox on you. I had Firefox crashing repeatedly on me with the snap version. Maybe switching to Firefox apt repo would help? (I tried the repo, but before I had chance to test it properly, I found I could use Debian instead of Ubuntu and reinstalled immediately.)
I just made the switch to ubuntu as my main os from windows. Firefox on windows never seemed to have any problems. Now I keep getting the same problem as your computer a. It doesnt happen every time, and i havent figured out the pattern.
But clicking the x to close a tab does nothing, middle clicking the tab still closes it. Any time this problem starts I also have issues using the mouse middle button to scroll (on all apps, not just ff) Very, very annoying. Since these issues seem linked it seems bigger than just ff.
Never experienced those with Firefox on Windows, macOS or a myriad of Linux distros along the years. Not using Ubuntu anymore, but when I did, I did not use flatpaks. That might be the origin of your issues.
At the end of the day, if you want to see these types of bugs fixed then by far the fastest way is to report them, which will probably mean you'll have to spend some time to track down what's causing that on your system. I have generally found reporting bugs to Firefox to be a reasonably positive experience.
Computer A:
Sometimes I cannot close tabs by clicking the X, or refresh/go-forward/go-back using the buttons next to the address bar.
Computer B:
Sometimes I get downloads that have "Unknown time left" (0 bytes/sec) when the X of X KB/MB is 100% and you can't remove it from the downloads dropdown.
I just discovered a new bug on Computer B, clicking the hamburger menu doesn't do anything.
Both are Ubuntu.
(I'm not a fan of the new menu in Firefox Beta for Android. I guess it looks nicer due to the greater whitespace, it just break muscle memory and has less options/selections.)