I have same problem. It seems to occur more while tablet is attached to Chuwi keyboard.
At Windows event viewer i have some errors
The local adapter does not support an important Low Energy controller state to support peripheral mode. The minimum required supported state mask is 0x491f7fffff, got 0x1fffffff. Low Energy peripheral role functionality will not be available.
If I wake up the Chuwi Hi13 from energy saving mode or from the deeper hibernation mode it does not return to the last active Windows app but it boots the EFI-Shell version 2.5. Another off/on and it returns to Windows. In BIOS I disabled everything except the Windows boot manager. Why this strange behavior?
Try disable Bluetooth from your device. Obviously if you are using BT accessories this is not convenient to do. But it seems that there is lot less waking up problems if BT is disabled. At least my low energy warnings are gone.