unfortunately it's probably going to get worse before it gets better. The fix for the geofences involved removing a timer that I was using to try and stop the flip flopping of geofence events within a 30 sec period. For example, if I get an enter event, I start a timer, then I get an exit event and then an enter event within the time period, I would ignore the last two geofence events. Unfortunately, for some devices the timer wasn't getting reset properly, so it never timed out, and thus geofences were not working.
I plan on re-implementing this with a timer that is working for everybody, but for now, it has been removed. I've been checking out other apps that have geofences and I see the same sort of issues in terms of the flip-flopping of events, and the change in geo-coords, so I'm not sure that we can fully solve this issue, but the timer when working, should dampen some of these.