I have a PM that won't mark as read or delete

I haven't come across this problem before, and the problem didn't come up in the archive with the search terms I used.

I received a PM earlier, which I have read, but it still shows as unread. I have also tried to mark it as read using the tick box on the message index, but still no luck.

Have also tried to delete it and it won't shift.

Not crucial, but it's annoying as it means there's always a new PM showing.

Just wondered if anyone has experienced this odd behaviour before, and, if so, if anyone knows how to fix it?

 

You'll just have to wait it out. It happens from time to time, and fixes itself usually pretty quickly.