I have had this exact issue off and on over the past few months. I am using Codex to help code my app and finally after some extensive debugging and setting up a simple test App specifically to test CloudKit syncs, Codex came up with a fix for me. In summary: Fixed CloudKit sync wakeups by replacing the shared SyncSignal subscription with per-device subscriptions. After this simple change, all the data sync between my MacBook Air, iPhone, and iPad has been rock-solid. Hope this helps someone.