I'm having the same problems about a week. Tried everything hard reset, usb boot, hot fix from Microsoft and calibration etc. Sometimes screen is working fine then deadzone appears with phantom touches. Doing software check from Surface website and Calibration with calib4g.exe fixing the phantm touchs but deadzone is not going anywhere.
I'm not sure it's software or hardware. My warranty is expired and also i'm living in a country Microsoft is not supporting Surface XD.
Maybe it's a firmware bug from the latest Surface update and MS will handle this?