Resolved -
The fix has been deployed. If you don't see the menu items come back, then you will need to update the app in you instance to pick up the corrected app descriptor that will return the menu items.
Sep 3, 13:21 CEST
Identified -
The issue has been identified and a fix in current being build.
Sep 3, 11:41 CEST
Investigating -
Customers have indicated that menu items expected of the app are no longer showing in Production
Sep 3, 11:40 CEST