I had to set a GoToSocial instance in the whitelist for Bypass MediaProxy as no emoji nor profile pics would show for me.
Unsure if this is likely to be something I have done with my configuration, or something weird with how they federate those. Just posting here in case I get more info to add to this at some point, unless someone has a lightbulb moment as to why.
Oh It just occured to me that it may be Firefox; if I attempted to open a link to the image (emoji or whatever) in my media cache it said it could not be validated.
edit: not just firefox, it is the same in any app. I am not sure why a remote fetch would show the image, but akkoma mediaproxy doesnt seem to have it. - and no I still have storage space for the media, so it’s not that.
(Also noticed hashtags open a link to the GoToSocial instance to view tags there, which is annoying: added to this post.)