Z-offset change always after every starting machine

Ender Series Creality Ender-3 V2
1

Hi,
is there a way to fix z-offset changing all the time ? (Ender3V2 + BLTouch)
Even if I power on the machine, making z-offest setup, and then while start to print, z-offset isn’t correct.
If I make z-offset on menu setup, and then power off the machine, then power on machine back and move z-offset, and then try to make z-offset setup again it always defer of about +/- 5-10

Thanks