This seems like a sorta obvious bug, so I was surprised I couldn't find a report on it. On the tag synonyms page (example), the tag itself is listed under the "Related Tags" sidebar.
This started happening sometime between Oct 11 2015 and Jul 6 2016, according to Internet Archive captures.
@Mithical I think you're using a user script that force-loads full-size avatars. Imgur strips out transparency when you use their resizer, so user scripts that "fix" transparency issues in SE avatars will load the full-size image. SOUP did that for a long time on the site before SE changes broke it.
Well, it would affect the user of the script. It wouldn't be smart enough to detect if there's missing transparency and load the full-size image for those ones; it would load full-size images for everyone.
@EleezatheOtherWorldWizard yes! Glad I still have some powers! So what's up? :D
@Krakalien not weird at all, imgur generates several thumbnails of the avatar, each with different size, and sometimes one of those is broken. So the one used for chat (think 32x32) got broken, re-uploading is the only way to "fix" it.
