CloudKit allUserIdentitiesFromContacts() failing due to too many requests (http 429)

Question

I'm making a simple call to fetch all app users in contacts:

let userIdentities = try await CKContainer.default().allUserIdentitiesFromContacts()

which fails with the message:

Request failed with http status code 429

HTTP 429 is the code for too many requests.

I get the same response in both development and production apps.

I've tried this in a test app that only makes this and no other calls, with the same result.

I have nearly 1,000 contacts on the phone where this fails. On another test device that only has 2 contacts, the request succeeds.

I'm assuming this is a bug, but just asking in case I'm missing something.