IOS GeoFencing: when a user leaves a region in the metro

What happens when the user has no connection and leaves the area that I control?

I am trying to implement something like "Significant Location Change" monitoring for devices without a SIM card. Therefore, I am mainly observing the region around the user. When he leaves the area, I get his new location and start monitoring the new area around his new location.

And it seems that everything is fine until I leave this region without a GPS or Wi-Fi connection (in the metro).

Also, I want my app to track while it is paused, so I cannot check the region after a while. I am using AppDelegate didFinishLaunching with a callback function to start a new region tracking.

Edit: My best idea now is to link CLVisit with CLRegion monitoring to check if the user has left the old region when it stops.