Now that users with less than 10K can see their own deleted questions, they can also add those questions to their favorites.
The action succeeds and the star toggles itself just fine showing the question is favorited, however it's not being added to the "favorites" tab.
I suggest one of the following to correct this behavior:
- Let those users see their own deleted questions in the favorites list, with the special background same way like 10K+ users.
- Don't let users with less than 10k reputation add deleted questions to favorites.