Issue with drawing polylines on iOS11 beta 4?

I'm having trouble drawing polylines, and I think I've deduced it to being an issue with iOS 11 beta 4. It was working yesterday with the same code, and now I've updated to beta 4 and it doesn't draw polylines.

Just confirmed this by trying it in Xcode 8 on iOS 10.3 simulator, and in Xcode 9b4 on the iOS 11b4 simulator.

Code:

import MapKit

class ViewController: UIViewController, MKMapViewDelegate {

    let mapView = MKMapView()

    override func viewDidLoad() {
        super.viewDidLoad()

        mapView.frame = CGRect(x: 10, y: 10, width: 300, height: 300)
        mapView.delegate = self
        mapView.region = MKCoordinateRegionMake(CLLocationCoordinate2D(latitude: 51.482736, longitude: -0.015253), MKCoordinateSpanMake(0.005, 0.005))
        mapView.delegate = self

        let coordinate1 = CLLocationCoordinate2D(latitude: 51.482736, longitude: -0.015253)
        let coordinate2 = CLLocationCoordinate2D(latitude: 51.482736, longitude: -0.016253)

        let polyline = MKPolyline(coordinates: [coordinate1, coordinate2], count: 2)

        mapView.add(polyline, level: .aboveLabels)

        view.addSubview(mapView)
    }

    func mapView(_ mapView: MKMapView, rendererFor overlay: MKOverlay) -> MKOverlayRenderer {
        let renderer = MKPolylineRenderer(overlay: overlay)

        renderer.strokeColor = UIColor.red
        renderer.lineWidth = 4.0

        return renderer
    }
}

iOS 10:

iOS 11:

Annotations are added to the map without issue.

Fixed in beta 5. We just had to wait.