Wow, never used Brave, but I haven't seen those logos either. I doubt they're even on the Lemmings Forum's servers.
According to Brave, what is the URL of that logo? E.g., right click the logo, view only that image. Does it show only the logo, or does it show correctly the lemming icon?
The first hunch is that this is a caching oddity in Brave due to a common image filename, but that would be an elementary bug, I doubt it. Still: Have you visited a forum about the soccer club AVFC?
-- Simon