Cannot change Primary Unit System xN (scale factor), it's stuck on 2.000

Hi,

as the title reads, I have some dimension lines drawn up and they show twice the real dimension. So I want to change xN under Primary Unit System, found when requesting the properties of the dimension. It is stuck at 2.000. When I overwrite it, it just changes back immediately.

What can I do, is it fixated somewhere else in the drawing, how can I change it?

Cheers,

Hugo