'Remove from favorites' not appearing?

So I'm trying to clean out my favorites of pictures I don't like as much anymore, and I run into one to remove, but when I go to look at it, it says 'Add to Favorites' instead of Remove. I try re-adding it to see what happens, but get the error 'Already Favorited' - but my name isn't on the list.

The post in question is post #211587. It's certainly on my favorites list, though you can't tell from the post.

It's a bug introduced by the changes from forum #7331. If you aren't in the list, i.e. one of the last six users to have favorited it, the link won't appear.

And it seems to be fixed now. Thanks, albert!