It’s probably a bug with adblock, but at this point I’m not really sure. But either way when Adblock is enabled this is what is shown (avatars are also missing from topics/posts):
Only a couple avatars are shown.
Disable it for this domain (or altogether) it reverts backs to normal:
This happened quite some time ago but thought nothing of it at the time, but I finally got irritated at it and decided to figure out what was happening.
Edit: Only seems to happen when the Antisocial filter is activated (which removes social buttons).