I have the same problem on 3 machines at the same time simeltoniuosly.. I changed the outlet plug.. turn off the lights and check all plug/jacks ,also upgrade machine to 103 software version , but the problem did not solve..
do you have any idea regarding this matter recently?
I had one machine with outlet power grounding issue. Moving it in another power source the issue was disappear.
Before that I replaced the touch screen and it's communication cable without success.
Also the artificial lighting (Flourescent light interference) in room may affect the functionality of the touch screen.
Another issue of this type of touch can be a bad connection in plug/jack's.
We have an Altalink running the (current) latest version of software.
The button pushes on the touch screen are erratic, you can see the button going down and it makes the sound but it doesn't do anything.
Can the touch screen be calibrated?