Home Z random different height.

[Niko0D]

Hi.
Can you help me please.
I have problem with z homing.
When i switch on printer and run z home. Z height set to 0. But if after that i run homing or mesh compensstion check i see for example 0.5 or 0.1 ( it random). If i right understand of course after z home it should back to 0.
I have corexy printer with head piezo sensor.

PS thank you in advance and sorry for my brocken English.