Confirmed in iOS 11.4.1 6S. The buttons would get stuck for about 10-15 seconds. Also the ads pop up at the least opportune time. i.e when you’re firing. After closing the ads then the buttons get stuck for for any given time. It’s working but not the ideal device to use. Have not tested on any other device so not sure if it could be my iPhone or just ads making the random stickiness of the keys/buttons.