Here's how I ran into what I think might be a bug:
Began reviewing First Posts via the new review feature on Biblical Hermeneutics.
Starting writing a comment on an answer.
Changed my mind and edited it instead.
Decided to also comment to explain my edit. Here's what it looked like:
Clicked on the "add comment" link. My screen capture utility removed the cursor, so you can mentally add the pointing hand cursor to the image hovering over "add comment":
Nothing happens. No comment box appears, no error, nothing.
What I expected to happen was that a comment box would show up so that I could add a comment. In fact, when I go back to the URL in another tab, that's exactly what I get:
If it matters, I'm using Google Chrome version 22.214.171.124.79 m. (Wow, those are some mighty long version numbers. While checking to see which version I have, I see there's another version available. I'll try updating and see if I can reproduce the bug with another post on some site.)
After updating Chrome, I found the same bug on a "Late Answer" review.
I abused one of the answers in my review queue and sure enough, the bug crops up if you do step #2 (start writing a comment), but doesn't show up if you just start editing.