When does google backup stop waiting? I enabled google backup on my galaxy S8 this morning. Photos synced in a few minutes, but all other items ("App data", "Call history", "Contacts" etc) have a message under them reading "Waiting to back up".

Under what conditions does the google backup start for these other items?


The phone is connected to Wi-Fi
The battery full battery
All OS updates are installed (or those that I've been prompted to)
No power-saving features are enabled
Tried attaching to recharger
Tried rebooting
Tried disabling/re-enabling backup


Is there something else I'm missing?  Perhaps there is a setting somewhere to control when backup should be performed?
As I just discovered, on a Note 8, screen lock seems to disable backup - including greying out the "backup now" button.  Disable screen locking and everything works.  Re-enable locking, and no backup.  Kind of strange.