The problem is that deep sleep (called lpsr) doesn't work. The device will go into the deep sleep but I can't get it to wake up.
With lpsr disabled sleep/wake via the physical button work, but automatic sleep doesn't as automatic sleep appears to use lpsr. So I have disabled automatic sleep in Oxide and I have no issues.
This issue is tracking adding support for lpsr and hopefully that fixes the automatic sleep in Oxide and other apps.