I have an Anet A8 using the Marlin 1.1.8 Firmware.
There are two (very much related) things that bother me:
G00 Z0 (after auto home from printer menu which places the nozzle at Z10.09 according to my settings) goes to Z5.
G00 Z-5 brings the nozzle down to the bed but I cannot see any offset like 5 mm.
In Ultimaker Cura I use the jog buttons (like I always do when leveling the bed) but every time I do this it seems that a Z movement of -5 is added. So I press jog distance 10 to the right. The nozzle goes to the right AND up 5 mm. Same with all other jogs. If I do X movements from the printer menu directly, the printer behaves correctly.
What's new is that whenever I connect or disconnect Ultimaker Cura, the display shows Z-4.99 on the display. I went through all settings even the Marlin
configuration.h to check where I could change this but didn't find it.
I am using a sensor as limit switch which pysical distance to the bed is 7.51 mm. M503 tells me that there was an offset (M206) of Z of 5. So I sent M206 Z0. In my firmware (configuration.h) the Z_PROBE_OFFSET_FROM_EXTRUDER is set to 0 ... hmmm, sounds incorrect to me. other z offsets I cannot see being different from 0.