Garmin Forerunner 935 battery drains rapidly. Watch was holding charge for 7 to 10 days. Last Friday something has changed and it now only lasts 6 to 8 hours. I haven’t changed any settings.

I also have this same problem. Seems to have started from a software update of some kind a week or so ago and now cannot rely on unit. Keeps on  shutting itself down whenever you try to initiate an activity