Something strange happens also to me with TB.
Sometime, not always and in a unpredictable way, when I delete a mail, it has been replaced by an empty one. This message has no content, no recipient, no header; its data is january the first, 1970, at 1 01 am.
This mail stays there until I select another folder from the treeview than I come back.
I use the unified folder.
Any possible explanation?