Ok, so I'm building with Unity and play testing in there and it's fine, no errors. I export a build to Xcode and build and run in there, I play the game extensively and it works fine. No errors reported.
Then when I archive and upload the game and download a TestFlight version - all of a sudden the main game action scene doesn't load. The loading screen is stuck and it doesn't fully load all features. The game background music is playing and only some interaction with menu items is available.
No crash.
What could be happening here?