x axis movement

I have a homebuilt machine based on a prusa i3 using a MKS genl 1.4 and I use repetier 1.6.1. When I print a model the z axis does not lift as expected and prints everything on the same layer. The model needs some support so I set the support option in prusa slicer. So far so good. The screen displays the z axis moves correctly and prints the first layer perfectly but the printer does not lift the z axis for the next layers. I discovered that if I kill the print and then do manual moves on the screen this continues updating the z axis reading until I reach 11 layers height. (screen update and no movement of the axis) This means the print should be at 2.2mm. If I continue with manual moves the z axis behaves correctly and lifts 0.2mm per move and the screen updates. I noticed that the z axis display starts at -1.35mm (my z offset is 1.55mm) and drops to zero as movements are given and then starts starts to increment the count until it reaches a height reading of 0.85mm, then it works correctly. I am using marlin 1.1.9. If I slice using cura the same thing happens. I have been fighting this issue for some weeks now and am at a loss as to my next move. Any help would be great!
Many thanks
Les

hey dude... I had some problems like this at the beginning and it that time I corrected the steps to mm number that it depends on which thread you are using...and also it seems like there is a Gcode mistake, what is the way you are using to control your printer?

The OP indicates some setup issues. A bed offset of 1.55mm wont give a good 1st layer so there may be some confusion between bed offset and sensor offset.
Since the 1st layer printed OK then the correct bed offset will be around -0.25mm.

Check your generated GOODE for your z axis lift command and see if it matches what your firmware expects.