The "add to some other anon collection, remove from ToT collection, re-add to ToT collection" method worked for me. Or, well, I should say, I added it to another anon collection, tried to remove it from ToT, never did get it to remove as far as I can tell, but was able to confirm it had revealed anyway. I will be keeping an eye on it to make sure it hasn't gone and removed itself from ToT after all so that I can be sure to put it back in it I need to. *kicks AO3 in some part that looks ripe for percussive maintenance*