that's a different bug..
basically a user who's allowed to write HTML is then quoted by a user who can't...
this is a 'problem' (feature) and has been all along..
the reason it is rare is that most sites don't allow HTML at all and rely on the ubbcode for what they need..
it's become less of an issue when i added the custom bbcode capability in 7.3.. that allows all kinds of new extensions..
so YES, you find a problem and it is a rare one.. and you can really 'solve' your problem by letting everyone post with HTML too.. but i would NOT recommend it...
get regexbuddy and make yourself some new custom codes for what might be missing