Couple of things.
If you are using autolocation for the geofence, make sure you under 'Exit Geofence She Connectios Lost' ( under Advanced'). Otherwise, a poor signal could cause your exit task to run.
If you are not using the auto location plugin, then, well, you should get autolocation - or use something other than GPS to trigger your profile (like a connection to your home WiFi). The native GPS trigger in Tasked is both battery hungry and relatively laggy.
Secondary to that - can you post the details of your entry and exit task?
Third, maybe you have a program or condition triggering on the ISY that you are running into. Many places to look.