At first, I thought maybe this happened when a user replied to me, and the user (including their post) was deleted before I read it. But when I reproduce that scenario, the notification disappears on reload. The notification here on Meta is sticky. It doesn’t disappear on reload and is still there after logging out and back in.
yea i think i know which pm too. a topic post in Support was moved to our team inbox around that time and the people who posted in the topic were removed.
I believe the fix from the other topic also fixed this. I tried your repro on the commit immediately before mine, was still able to reproduce. I then reverted to main and tried again, and there’s no stuck notification.
I also think the migration script in that fix should clear up your old one. If it doesn’t, we might need to look into that separately.