I created a realm and downloaded a resource pack (a shaders pack). The pack didn't work for me, but other players reported that it worked like normal for them. Later, I tried to remove the resource pack but failed. I went to the game directory and deleted it there, but it still applied to the realm. Also, the pack didn't how up in the "active packs" list of the realms settings. So far I haven't solved it, but I might have complicated it a bit by downlaoding other versions of the pack (which I all deleted). There might be a chance that it's gone but people haven't bothered to tell me or something, but I trust them and the whole packs list is still working weirdly so I think the issue still exists.