Earlier on SO, a reply was posted to a comment I made on this answer. My username in the reply was italicised and I didn't get any notification for it, which I assume is because of the letter-for-letter match that comment replies use. If my guess is right, should the comment reply system ignore markdown for the purposes of matching usernames?
No, this is just a user oddity. For some reason that user formatted the comment as
*@Niall C.:* I'm not sure that the distinction between accessibility...
In such cases (never seen one before) the user is simply not following the standard formatting convention, so it can't be expected to work.