BUG: WPMU DEV mentions system messed up

The mentions system here is really messed up. I like to write in this format.

Hello ">">@username,<br />

">">@username,<br />

For some reason, when I write like that, the whole paragraph gets linked to the profile, you all need to get a better handle on this. It was working fine the other day, then you switched over to using usernames instead of display names, and that is when things went downhill.

EDIT: Check out what happened above, it did it again. I was only writing it like this.
Hello @ username,
Sorry for the space, trying to make it not make my example a link. This is not good.

Edit 2: The words Paragraph. were linked, as soon as I edited the post, then saved, you can see the result above. Strange.

Hope this was useful information.