If you are on android, try downloading the GPS Status app. In that app, go to the calibrate compass settings and see if it reports as red. EVERY time I had issues with my phone jumping in and out of geofence areas, this was the cause (Any magnetic mounts or cases with magnetic closures will instantly decalibrate the compass)
If it is red like the above, you have to rotate it on each of the axes until it returns to green.
