I'm having the same error but with a MKCoordinateSpan. This is my code:
let span = MKCoordinateSpan(latitudeDelta: 0.005, longitudeDelta: 0.005)
...
let currentRegion = MKCoordinateRegion(center: lastCoordinate, span: span)
I hope they will release a fix, right now I have to change the latitude and longitude delta to 0.05 and everything works fine.
Cheers.