This has happened twice to me now: once in Cyrodiil, once in Rivenspire while questing. As the subject says, I've randomly found myself unable to weapon swap by any means, including clicking the weapon swap icon on the skill screen (if I click it, it shows the other weapon bar, but my character doesn't actually switch). I can still use my abilities normally on the weapon bar I'm stuck on, but attempting to weapon swap does nothing.

In both cases my only fix was to log out and log back in again. Reloading the UI didn't do anything. This has never happened to me before Wolfhunter, so I'm guessing it's a bug introduced by the DLC.