iCloud Sync not working with iPhone, works fine for Mac.

I've been working on an app. It uses iCloud syncing. 48 hours ago everything was working 100%. Make a change on the iPhone it immediately changed on the Mac. Change on the Mac, it immediately changed on the iPhone. I didn't work on it yesterday. I updated to iOS26.4 on the iPhone and 26.4 on the Mac yesterday instead.

Today, I pull up the project again. I made NO changes to the code or settings.

Make a change on the iPhone it immediately updates on the Mac. Make a change on the Mac, nothing happens on the iPhone. I've waited an hour, and the change never happens. If you leave the iPhone app, then return, it updates as it should.

It appears that iCloud's silent notification is to being received by the iPhone. Anyone else having the issue? Is there something new with iOS 26.4 that needs to be adjusted to get this to work? Again, works flawlessly with the Mac, just not with the iPhone.

Wish I'd reported this weeks ago when my iPad showed this symptom on the iOS beta, but I'd assumed it was due to me using a sandbox user since Apple was so bullish in their WWDC 2023 video about the number of test cases they'd created for CkSyncEngine.

I'd also created a feedback before discovering this thread (FB22344526)

Easy to reproduce - the Apple sample app fails. Hoping it gets taken seriously.

iCloud Sync not working with iPhone, works fine for Mac.
 
 
Q