Whenever I create a filtered deck or a custom study session, all the cards that go into it automatically show up as a part of the deck that is first in alphabetical order, only when editing. When browsing the filtered deck, they look normal deckwise—in their proper decks—its only in the editing window of an individual card they show up as the alphabetically first deck.
This is a problem because I have cards across different decks/subdecks with the same title, and when reviewing I should be able to double click from my side and catch a quick glimpse of the deck so I can answer likewise. Which I obviously can’t. Why is this happening?
It looks like this was reported a couple months ago and there were some issues with the initial attempt to fix it, so it is still unresolved.
While you wait for a fix – have you considered displaying the name of the {{Deck}} or {{Subdeck}} directly on your card – Field Replacements - Anki Manual? You could add something subtle to your templates, in a small font. This could actually be a long-term solution as well, because it will save you from having to click away from the card and back to check what deck it is.