Machine occasionally is stuck jogging

I have an issue that I can't seem to solve. While jogging to move to a position or touch off, when I let go of the mouse button the machine continues to jog. If I hit the Stop button it stops, otherwise it just continues into the table. Frustrating! I figured I had a bad mouse, so I replaced it.and the keyboard. Still have the issue. Anyone have this issue before?

Oh come on!
What CNC machine?
What PC?
What OS?
What pulse engine?
What ...

Cheers
Roger