Hi, I have exactly he same problem on my wife's 9790 with hotmail on Orange. Previous 9780 with on smart carrier and mail account didn't have the issue.

Lots of others do too by he look of quick google search like the below link but no answers that I can see. Can anyone help? All appears to be hotmail on BB7.

......forum.vodafone.co.uk/t5/BlackBerry/Text-in-emails-duplicates-itself/td-p/1005861]Text in emails duplicates itself - Vodafone eForum