Hello
debugged HF_SET_STATUS and found the Reason:
There is a Customizing Topic in TA sm34 AIC_SETTINGS
Select Transaction-Type (e.g. ZMMJ) and then check the Setting under
"Specify Partner Assignment and Check"
I had SMCD001 for Userstatus E0002 in the Table. So this Partner got overwritten by the BP of sy-user when saving the Status E0002. Deleting the Entry helped. Now the Partnersetting is left unchanged.
Just in Case somebody has the same problem.
Regards.
Rolf