BUG CONFIRMED. If you edit an older message containing markup, the markup is converted into HTML and does not render properly when you save it. Editing a message you just posted works fine. I don't know why the timing is an issue.
I just edited this to remove ---> these <---- italics. It works fine.
Pardon my dust. I am testing a theoretical bug. I'll be back <i>tomorrow</i> to confirm (or disprove) my theory. Thank you for <i>not</i> listening. Carry on.
I don't know if this has ever come up, but it seems like explicit usages of "@SomeUserName" shouldn't assume the user was replying to the last message SomeUserName sent; that seems to usually not be the case
People use the reply link even if it was the last message; when people actually type out @SomeUserName it's to ping that user about something totally unrelated to the current thread