I have the same problem! For some reason it only happens texts. I have TMobile service and the latest upgrade as well. The only solution i've had for it so far, is to remove the battery and put it back in. It's as if its caching some text's somewhere in the memory temporarily, but i cant find where. i cleared out the inbox, sent folders for email and for sms as well. but nothing. let me know if you find anything else.
thanks,
-doug