Sovol S07+ doesn't save negative z_offset correctly - firmware bug

When leveling bed via the menue I’m getting a Z-Offset of -1.95
When saving and restarting the printer it changes that value to +1.95, so a difference of 3.9mm - it prints into the air!

So I have to lower the Z-Axis every print manually by 3.9mm while the print starts -.-

How to avoid that?

Kind regards

Addition: I bet this guy has the same problem