Confirmed here also on FF. This link is problematic https://blenderartists.org/c/artwork/forum-gallery others under c/artwork/ seemed ok for me.
Tried again, this time BA logos were further down the results. Caching affected?
Logged out, cleared cache manually. Traditional & Sketchbooks sub forums were also affected when checked.
A room In Focused Crits is always a BA logo, probably the image link (wordpress).
Quickly scrolling may influence it too. Get to bottom of loaded list, more topics load, scroll further, some newly shown thumbs also display the logo now. Seems image size and external links could affect it also. Time out / load issue?
Animated comic Missing last post (separate issue)