I searched for this issue and found the following topics which describe my problem:
It seems this has been fixed in 2017. However I’m experiencing the same issue (I’ve only had Discourse installed since 2019, and have updated it frequently).
The issue is: I have set Badges to be set as titles from each user’s preferences panel.
However, when I set my title to anything, it reverts back to (empty) the following day. Is anybody experiencing the same problem?