New App Experience: Cannot View Published App / "All" results in duplicate tab

bajimmy1983 - I ended up on a screen share with Power BI support yesterday (after submitting a ticket), and while they couldn't yet identify a specific reason for the error, I ultimately unpublished the app, and then published it anew, and it is working now (including with re-testing deletion of the primary audience tab). Reorganizing the audience tabs is still not working, but I have a working app again.

Important note: unpublishing the app will cause any individual-level bookmarks, comments, etc. to be lost. So, depending on if that is pertinent - this route may or may not work for you. If you do this - make sure to take a screen grab of the reports included in the app and any audience settings you entered, as you'll have to reconstruct the app from scratch.