Layer height not used correctly

[BelgianGuyWithALaser]

Version
2.2.53

Operating system type + version

Windows 10

3D printer brand / version + firmware version (if known)

CR20PRO (not stock) klipper firmware

Behavior

layer heigth not used as Filled inside the settings.
Set nozzle to 0.4mm in printer settings, set first layer heigth to 0.3 (or 75% with both versions it's not working) slice and check layer heigth in the preview. it becomes 0.32 instead of the asked 0.30.

expected layer heigth of 0.30,
Actual Results received 0.32

• Screenshots from SuperSlicer preview are preferred
  
  

Project File (.3MF) where problem occurs

layerheigtherror.zip

[supermerill]

You have your z_step at 0,04: so your layer height can be 0.28 or 0.32

[BelgianGuyWithALaser]

even when setting the Z_step to 0 both it's still at 0.32

[supermerill]

That's a refresh bug. Set the first layer height to something else then back to 75%