You cannot change the register group due to register relationships

What causes this issue?

You tried to change the data for the register group. This is not
possible, because it would affect the dependent data of the register
relationship, and would result in inconsistencies in the data of the
sample register relationship.

System Response

INCLUDE ISU_VERARB OBJECT DOKU ID TX

How to fix this error?

Change the data of the register relationships.
Change the data of the register group.

Procedure for System Administrators

The system issues an error message and will not allow you to continue with this transaction until the error is resolved.

Error message extract from SAP system. Copyright SAP SE.