Someone mentioned a glitch with the GPS not shutting off. I noticed this too, with the current released (not beta) version.
I was caching yesterday, and after some frustration with GPS position not seeming to update as I walked, I switched GPS compatibility mode on and continued. Maybe that's relevant. (I can't remember if I switched that mode back, but had more update glitches.) Later at home I noticed I still had guidance on, so I cancelled that and turned off the screen, went to bed. The GPS should've turned off at that point.
Next morning, battery was abnormally low, and GPS was still active. I did some experimenting with that mode setting, but found nothing conclusive. It seems to be working okay now.