Using Touch Probe - failure to comply

Randomly when using the touch probe the bit taps on Z then does not over shoot the plate and jams causing damage. The router has been sent to "home all" in the first instance manually guided over the touch plate hole, then probe conner command given.

Also again randomly - example when engrqaving text the text is cut in a totally different position form the screen display.

Thoughts? kind regards jjb