It seems no one noticed (which is a good thing, means it's working), but I have changed the private message page mechanics. Not sure though if it helps with this problem.
By #316057 at 01,Apr,15 02:11
This happen about A Week ago That I notice --------------------------------------- added after 4 minutes
It still happening this guy pm 4 hours ago in just came on again 2 times --------------------------------------- added after 7 minutes
I could be wrong but I've been told it's from people using their phone and pressing the back button after they send a message to go back to previous page instead of closing the window.
By #358797 at 31,Mar,15 05:24
Yep! I'm strictly a mobile user and it happens to me all the time. Also does it if I hit the refresh button. It's definitely annoying at times.
--------------------------------------- added after 4 minutes
It still happening this guy pm 4 hours ago in just came on again 2 times
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Sorry had to bock him this annoying