I just discovered tonight after downloading the new version of Apple TV that it erased all my favorites that I had on my podcast on Apple TV. Was not happy at all. Apple technical support had no idea how to fix it.
One of two things happened.
1. Apple intended not to make it work and forcing us to resubscribe to that specific podcast that we enjoy.
2. They had no clue that it was going to do that. The only way to work around this is to resubscribe to your favorite podcast. There is no workaround other than that.
Apple has no clue fix it at this point unless there's a future update... they sure blew this one
So before you update, make sure you write down all your podcast and be prepared to resubscribe to each and everyone of them.