After installing one of these heated desk mats on my cold work desk, I've noticed some erratic behavior on touchscreen devices I develop software for when they're laid down on the mat. Most noticeable on iphones, when the heat is on, part of the touch grid becomes unresponsive and sometimes receives ghost touches. It happens regardless of device temperature.
I'm posting here in EE, because I have a suspicion the cause might be some sort of electromagnetic interference. I'm happy to move it elsewhere.
There seems to be a cause-effect relationship, because it's happening on multiple devices from different manufacturers. What is going on here?
Here's a video demonstrating the effect: https://youtu.be/0jz8HaytlEs