Looks like the CloudKit sync issue in *OS 26.4 is real (I can repro with all of my apps), and has the very distinct potential to lead to catastrophic data loss and/or sync conflicts across effectively all apps. Apps only receive changes from the cloud after being quit and relaunched.
If Apple hasn't pulled 26.4 already, it should do so immediately until there's a fixed build
@stroughtonsmith @lukaskubanek FWIW, the game I'm developing, up until 26.4, would sync every move across all devices almost immediately. It was amazing and actually became needed for me to include tvOS support.
Now on 26.4, iCloud ~maybe~ works to leave the game in the state it was in so you can continue elsewhere, but even that's not reliable. Spent way too much time on this to only shrug and stop.
Steve Troughton-Smith
Jeff