Sideloaded Oculus Go Unity app restarts after exiting sleeping mode (in dev mode)

The question is in the title.
I made a Unity app, sideloaded the apk with adb (My Go is in dev mode). If the Go enters sleeping mode (after 15s - 15mn depending on the settings), when exiting the app restarts from the beginning (Unity Logo etc) and it takes a while (about 2mn).
Before (maybe before an automatic update of the headset ?) I never had this problem.
I tried the same apk on the quest, no problem, it does'nt restart the app after exiting sleeping mode.

I tried several ideas without success, factory reset, kiosk mode etc...

Some questions : 
- does anybody have the same issue ?
- is there a way to avoid entering sleeping mode (of course this will quickly empty the battery...)
- is there a way to turn off only the screen when entering sleeping mode ?
- is there a way to install an older system (or firmware) version ? I know that it is possible to disable the automatic update process, but I am afraid this can't be done the 1st time you setup the headset, which is configured with the last version.

Any help very welcomed !!!