I think the tab is redundent and should be removed.
Items do not load at all from that specific tab, and others have said what happens is that if you favorite an avatar, you are automatically subscribe to that avatar, it is loaded, then you are automatically unsubcribed.
Even when trying to wait for the Subscribed Avatars page to load, it never loads.
It should just be removed in the next update since we have the Favorite tab and is essentially the same thing but actually functions/loads.