It is stated in the stackoverflow FAQ: http://chat.stackoverflow.com/faq#formatting
*italic* or _italic_ **bold** or __bold__
so when I type three * followed by a word followed by another three * I expect to see the word to appear to be both italic and bold. Now this is work correctly.
Today I was formatting some message in a chat, I accidentally typed in this:
*this = ***that***
It appeared to read "this = *that" (with 'that' appeared to be bold & italic).
Is this not a bug?