I have the same. Was all playing fine then today tried using WidevineProxy2 to download a free video - which didn't work, got a file but junk/still encrypted - and then subsequently kept getting the message about "cannot play protected content".
As soon as I logged out the same video played fine on the same device, and the same behaviour when logged out/signed in on a different device, so it would appear they're tracking attempts to circumvent somehow. Presumably including a user ID in the (mangled) keys that WidevineProxy2 picks up.