Yep! After Michael pointed it out, I reported it to bugs and it confirmed their suspicion that it was a logged out/in exception that was causing this to happen. So the quick fix for now is : Make sure you are logged in. and the permanent fix is in the works for it not to matter whether you are logged in or out. Thanks for the feedback guys, and good sleuthing.
Making sure you're logged in is not necessarily correct - see below. Not being logged in makes no difference, as a designer will not be able to see their own private models anyway.
Hi guys, Just an update, this bug was fixed with this weeks release! As always, thank you for the feedback as we continue to improve! Best, Natalia