I have an iPad Pro 12.9" wifi. Ocassionally while using a midi keyboard or similar controller iTunes will start playing. It'll even play songs I have not downloaded. The app I was using was AUM and it's file player. The other apps were different each time. The one midi controller is Arturia mini lab. The other was Sonuus i2m. I've read others have this issue with Bluetooth devices...I am not using Bluetooth at all. Most times I even turn off the wifi.