Skywriter (Fullsize) not working correctly


I’ve bought a fullsize Skywriter and it’s returning very weird results. I get the same on an Arduino (I’ve tried UNO and Mega) as well as a Raspberry Pi. Basically it only works if you touch it and even then not every time, plus it gives really strange xyz results with seemingly random numbers.
I’ve tried the firmware update that was posted elsewhere, but that didn’t seem to make any difference.

Any suggestions or is it broken?

Many Thanks