If you use the ipad pro's magic keyboard cover, and you do a five-finger app switch on the screen, the trackpad will stop sending PointerEvents into the browser once you return. You have to throw away the app and start over to get PointerEvents to work again. This happens in WebViews inside apps as well as safari. Note that MouseEvents still get sent. https://codepen.io/msfeldstein/pen/jOmpowb
*** This bug has been marked as a duplicate of bug 236390 ***