If anyone else runs into this issue, I recommend looking at this article: Deploying an iCloud Container's Schema.
dougholland
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I hadn't used CloudKit before and didn't realize the additional steps required to deploy the container into production. I should be able to resolve this issue now before the next TestFlight release.
I think this maybe caused by the other two devices using the development container and the third device, which never had a development build, using the production container. All three are using an Apple ID from the internal testing group and so I would have thought all three should be on the same container.
This change needs to be made by Apple Developer Support. Give them a call and they can resolve this.
The SwiftUI version of MapKit is supported on visionOS although it really should embrace 3D and let users explore maps horizontally that have contoured terrain and 3D roads, bridges and buildings etc.