Problem on the pad, the surface: It is fraying at the edges after a short time out, the same thing - then happens on a smaller scale also in the center.
There, too, then tiny threads or nodules on the surface - about like a often washed T-shirt or sweater - only much smaller, barely visible, was then tried only once on troubleshooting, batteries, various mice. One can only see properly when you lift the pad and considered up to the light, and then it is immediately clear why.
As a result of imprecise sampling and short dropouts.
Bought a new pad - everything back as it should be - this one I have discarded.