When I open a few pages in new tabs and then switch apps or lock the screen or press the home button (ie. ''minimize'' Firefox), all the opened pages which I haven't seen would just vanish. For example, I opened 10 articles from search results while doing some research, see two of those tabs and then make a quick switch to a messaging app. When I come back to Firefox, it'll show only the two tabs that I've seen and the other 8 would've vanished.) This has been happening for multiple weeks now, but still hasn't been fixed even though it's a pretty major issue. Tried on multiple devices running Android 10 and got the same results.