Here's what is in the Mach Manual:
"In response to this command, the machine moves the controlled point (which should be at
the end of the probe tip) in a straight line at the current feed rate toward the programmed
point. If the probe trips, the probe is retracted slightly from the trip point at the end of
command execution. If the probe does not trip even after overshooting the programmed
point slightly, an error is signalled."
However, I believe what you are saying is correct, because I have not seen it move due to G31 after the probe touches. But again, I was simulating the probe by touching two wires together so I thought perhaps it was moving ever so slightly and when it did not see the probe break contact it raised an error. Assuming you are correct, I am guess I will have the same wierd probel with the moves after G31 when I truly do use a touch plate. I suspect this may be a SmoothStpper issue, but will investigate more to see if I can better characterize exactly what is happening.