Hey Bryan, a bit of extra info for you. As @JammyDodger mentioned, Discourse.User is not recommended, but we didn’t actually intend for it to break yesterday. I’ve just fixed things up, so if you update your forum to the latest tests-passed then things should start working again.
Instead of an error, you’ll see a warning in the browser console. You should still aim to track down where that’s coming from and update it - eventually we will be dropping support properly.