It doesn’t seem like this could be caused by the card templates then. Does this happen for just one note type or several/all note types?
Are any of these type-your-answer notes/cards – especially ones that rely on an add-on on Anki Desktop?
The only other suggestions I see have to do with switching to the v3 scheduler, but since the v2 scheduler is no longer supported (I assume that happened in AnkiMobile along with the other apps), as long as you’re using the current version of AnkiMobile, you’ve already done that.
The obvious work-around for now is to exit your study session, to the deck/menu screen, before leaving the app. We’ll see if @dae has anything else he’d like to know.