I found out it works in simulator only if you log in with a sandbox user id ( tester account ) - same user type one would use for in app purchase testing.
The weird thing is that it’s using a sandbox version of the store ( not the development one) and there’s no option in CloudKit database viewer to see that sandbox store …
I hope it goes back to working as I like having my phone app and simulator app having the same data .
I’m sure you know it’s works fine on the device - just in case you are blocked by it in any way.