If it is under warranty then you should contact Moto Customer Care and get an RMA to send it in, your assumptions that it is the digitizer are likely correct, although that means the entire screen assembly needs to be replaced.The touchscreen goes haywire. I go to press the number 4, and 6 is the that gets toggled. It's still under warranty and I'm 85% sure my digitizer is responsible. Until it's fixed I'm using my spare LG G4 (with a cracked screen nonetheless).