Ionic4 - First login works, but any further login won't close the browser (only iOS tested)

Following the tutorial or even downloading the example project works well for the first login on iOS. But once I try a second time, Safari won’t close the browser and leaves a white page. When I try to logout it actually always leaves the white page. I tested with Ionic 4 and iOS 13. My feeling is that iOS13 might have changed something… Anyone any idea?