Firefox keeps losing its bookmarks

A question from a novice Ubuntu-user please:

When I start Firefox (version 94.0, 64 bits) from the taskbar, the program does not run, I just see the little Ubuntu logo spinning around during 15 seconds.

When I start the program a second time, the program runs but has lost all of its bookmarks. I have to import them from the backup copy.

Next time after boot-up, the same problem. I am using Ubuntu version 21.04, problem was not there when using 20.04

Any Help is appreciated.

Thanks for the reactions so far.@Algnis: how can I tell if the Firefox that I am runnng is 'deb' or 'snap' version ? Please bear in mind I am a novice..

It's a bug with snap firefox

sudo snap remove firefox 

rm -rf ~/firefox

sudo apt update && sudo apt install firefox

(sudo won't be generally required to remove snaps)