Just for reference, see http://www.blackberryforums.com/gene...ml#post1530852
Regarding google, you could try moving your old emails out of the inbox (if that is where they are) and then move them back into the inbox. I don't know if that will work or not. I works on Yahoo, as I recall, and that's what made me think of it.
Just FWIW, dc's case is the only other one besides you that I personally know about. That beta has my vote as the cause of the problem.
Also, I'd set DM to automatically backup on a daily interval.