My Garmin enters in power save mode even during activity

Hi,

I did today a run with my Garmin Fenix 5 plus. It was the first after a few days of inactivity and I think it was the first after new firmware upgrade.

well, my watch every 5 minutes entered in power save mode even if I was running.

GPS signal was good, the watch was recording and even if I pressed lap or other button after 5 minutes I was back to the watch face and I had to manually press the start button to return to the activity. 
I already rebooted the watch. 
any other ideas besides wiping and factory reset?

thanks. 

   Gianpaolo Racca