Bimmy I wonder whether this is a side-effect of the temporary removal of NFC auto-turn-off
Unlikely. Looking at the change to remove NFC auto-off feature, other auto-off features shouldn't be affected.
Bimmy Have you tried disabling the feature, reboot, re-enabling it, maybe with slightly different time to increase chance of fresh configuration in that area?
Agree that this is worth trying to see if it helps.
Also, looking at how WiFi auto-off works, it will also not automatically turn off if the wifi state is connecting, authenticating, or obtaining an IP address, and it looks like the timer will automatically reset if the state changes. So if the device tries to connect over and over again for any reason, auto-off might just not get a chance to run.