Another update - I tried to upload something with copyrighted content on it to another channel to trip content ID, then delete the video and see if the tab went away. Content ID was indeed triggered, HOWEVER, it seems YouTube has phased out the "Copyright Notices" tab, as it did not appear, but in the video manager, underneath the view count, likes/dislikes, it said "Contains copyrighted content." Does this tab no longer exist? Why is it stuck for me?