This has been around for a while (a year at least, since the redesign), but it still bugs me on an almost daily basis, so I will post it again, in the hopes it will be bumped in prioritiees.
So, if you have a comment with any kind of html tag or bbcode it seems to work. But if you edit it, the bbcode is shown as html, which is fine, except when you save the comment, the html is all escaped and translated to literal text.
To replicate, create a comment that refernces another user like say ".@smuggins-4944401". When you edit, it will display as html href tag. However, after you save it shows the literal href tag (escaped html). So instead of rendering the link, it shows it as plain text.