I have been using the "install as app" feature in Firefox for Android for years. It is a great feature for appifying services that don't have a dedicated app and for getting around poorly implemented stand alone apps. Last night I tried to delete a redundant "app" icon from a web page that I made a shortcut for in Firefox. Apparently removing the shortcut icon via the normal Android UI also completely removed Firefox and all my other app shortcuts that I made in Firefox before. Please fix this bug ASAP if you are able, I understand it also may be an Android thing you can't fix. I have not recreated the bug because it is very annoying to have to reinstall and reconfigure Firefox.

Good luck!