update from u/JagexAzanna, "Doing a relog should solve it, basically a new music track was added to an achieve and so you login, the check says your missing the music track, you then unlock the track. Doing a relog does the check again and solves it."

title says it all, logged in, cape override was disabled, rectified by a simple equip of the cape but putting it out there incase anyone else has the issue

reequipping your cape post login still works as well but relogging is faster