I'm hitting the same issue. Deploying the Development schema to Production fails every time with HTTP 500 internal-error on the …/schema/<developmentSchemaId>/promote request. It fails from both the "Changes" tab and the "Diff View" tab of the Confirm Deployment dialog. detailedMessage is undefined. Filed as FB25280547, with the container ID, request UUIDs and screenshots. Example requestUuid: 7f4aec62-6ead-4e86-8784-77be751d3622 The diff is purely additive: Core Data / NSPersistentCloudKitContainer fields such as _ckAsset assets, CD_moveReceipt and one new string field, plus QUERYABLE indexes on ___recordID. No type changes and no removals. I tried refreshing, re-signing in, and a private window. It still fails. This blocks our App Store release because the new build writes a field that Production doesn't have yet. Could someone from the CloudKit Console team take a look? Thank you!