This is a tricky one to describe, but I'm pretty confident it's not something I'm doing wrong, it's something that's broken in PowerApps.
I have an edit form connected to a SharePoint List. On that form is a dropdown, the items property of which is set to the display the Choices defined in the list settings.
At first that worked - you pull the dropdown, the items show. In future edits to other parts of the app, the app was published and the dropdowns stop working.
Here's what's weird. If I go to the Items property of the dropdown and make a change - literally by deleting and then re-typing one character, it magically starts working again. I publish the app, it still works, all good.
But next time I publish it breaks again, and I can still fix it by literally re-typing the entry in Items.
I have a totally different app with an edit form pointed at a different list and site. When I select an item from a browse gallery I pass the ID of that row into a variable, and the Edit form Item property has a formula to do a LookUp for the item with that ID. Again, it works fine... until I make a change and publish the app. If I want to get it working, I can make a change to the Item property - again, that change being literally re-typing what was already there, and it's good to go again.
Obviously I can't keep re-typing all my formulae each time I want to publish!
Is something broken here? Both apps are in the same tenant, I haven't tried it in my other tenant yet. This has been going on for about 3 weeks.