Works on iPhone fine but a grid appears on iPad – Heat Pad - Relaxing Surface Review

I’ve had this app on my phone for a while (iPhone 6s plus) and it works just fine. I recently got an iPad Air 3 and when I downloaded it every time I use it a weird grid appears. This only happens on the iPad. Not sure why, but it makes using the app a lot less fun on the iPad. Still a good app on the phone, but this bug needs to be fixed.
Review by shoobiedooble on Heat Pad - Relaxing Surface.