Issue: "1 Unread Visitor Messages" not clearing

since 06-01-2012 I have "1 Unread Visitor Messages" which does not clear while visiting "My Profile" -> "VM's" tab

that's really strange, if I get new VM's the counter increases normally
but when I visit my VM's to see what's new the "1 Unread Visitor Messages" will remain in the "Notifications 1" on the top of the page
the only thing I have not tried yet is deleting this specific VM from which I think triggered this bug

I would love to keep that VM ... especially since I don't know if deleting would really solve this problem ... ...

can you maybe manually clear this counter for me so that it will be back to normal again??? ... ...