From the community on Github:
Hi, thanks for the module!
I ran into a situation where a convoluted set of user actions on iOS (device rotation, textfield focus/blur, tab swapping) ended up getting the MKMapView into a state where if I called mapView.addPolygons from the JS, they wouldn't actually render until the map was zoomed or panned.
This was the only successful workaround I could find. I also tried posting different combinations of setNeedsDisplay, invalidatePath, and setNeedsLayout on both the current and main queue for the mapview as well as the overlay renderer.
That said, it was a tough bug to reproduce so its possible that this doesnt actually fix things in the end.