People seem to be interpreting your question as asking about what happens to a user’s DQA votes after they delete their account–which is a valid question–but I think you were asking about the mechanics of another user’s vote persisting when the most specific ID has been deleted.
I submitted a feature request a couple years ago for the same issue, albeit with a different etiology (taxon swaps): https://forum.inaturalist.org/t/reset-can-the-community-taxon-still-be-confirmed-or-improved-after-taxon-swap/9266