It's an old trick but Apple fix it on some betas in iOS 7. I wonder why it works again with iOS 8.2 Betas & know what 8.2 betas doesn't have expiration dates. Lol. Apple is probably loosening up or following the path of Microsoft.
Be very careful on Shift+Restore if your not a dev or you have unregistered UDID, Apple could lock you up on Activation screen & can't restore back to 8.1.3. Though I only found limited cases on this with iOS 7 but who knows, only Apple does. Lol. DFU mode then Shift+Restore to 8.1.3 IPSW will do the trick mostly if you will get stuck with activation.