I might have run in to the same problem, though I initially attributed it to the 27 beta of XCode / macOS (reported as FB23688931). (This was with mostly the default SwiftUI + SwiftData + CloudKit template app, though I added the iCloud capability and enabled CloudKit. The app came with the “App Sandbox” capability configured by default). After verifying the fix with the print(CKRecord.self) as suggested above, I worked around the issue by explicitly adding “CloudKit.framework” to the “Link Binary With Libraries” setting under “Build Phases” which also fixed the problem.

This seems to have been fixed by iOS 18 Beta 6.

The feedback report is FB14381484 (I actually created that before the initial forum post). I have added an update with a sysdiagnose with the Location Services debug profile active, and included relevant timestamps in the report. I don't have shareable sample code at the moment.