I think that's by design - if a regular member edits a post with HTML (if they dont' have the ability to HTML) you want to "break it" otherwise they could insert dangerous stuff in the post. So it reverts to UBB
If the post is HTML and everyone can post HTML - then the formatting should be retained. (If not then that's a bug) But allowing HTML in your forum to general users is a
very bad and dangerous idea.

Youv'e got a high potential of getting hacked.
