I am sorry to hear about this. Are you automatically updating or manually downloading updates to Firefox?

I get a notification that there is an update available, and I click update. So I think what happens is that the stuff gets downloaded but then the install part doesn't happen. ( It is sideloaded with the ES Explorer.) I then go in and try and install it again but nothing happens. I can't seem to find the place where I originally downloaded FF without going through the Play Store. If I could, I could do manual updates or probably uninstall and then reinstall. I'm not tech savvy so I just wait for the next update, which, if history repeats itself, will install just fine. In the meantime I use Aurora or the Beta Firefox.

May I follow up with you that this did not happen again after the next update, it was actually on day after your last post.

After the next update which was about a week ago, FF worked ago. There is another update that just arrived - I lost track of the version - that I have not applied yet