After changing bits and probing Z, the Z is way off?

Final update on this for me I hope. The connection for the z cable was not clicked in completely so it was intermittent at times. This was a fault in the dimensions of either parts or access. I had pushed it in as far as possible. See the picture. Upon taking it apart, I was able to click it in place. It still does not look perfect. The connectors may be slightly damaged.