> What? The app is infamous for just "forgetting" tickets

Citation needed. I've never heard of this being an issue (certainly not an "infamous" one) and almost everyone I know constantly travels by train and uses the app regularly. Maybe you're mixing things up with Deutschlandticket apps by regional transport associations, but that's not DB's fault.

Tickets get hidden from the default view once they're expired, but that's to be expected and you can press the prominent "Previous trips" button to see them.