Is it just one saved messages or all saved messages?
It may be a corrupt BTR file. The status file may be corrupt causing issues would be just a guess. But if it is just one message would suspect that message has a issue. You may want to try to forward it to another mailbox or even the same mailbox then it should become a new message and see if it does the same thing.
If you need assist with copying BTR file over to try to correct let me know.

mjc