This assignment causes an inconsistency in the group hierarchy

What causes this issue?

Recursive group structures are not allowed. You treis to assign a
grouping WBS element to another grouping WBS element, which itself is
assigned to the first grouping WBS element.

System Response

INCLUDE NA_ALLG_NOVERARBEITUNG OBJECT DOKU ID TX

How to fix this error?

Check the assignement of the WBS elements to grouping WBS elements and
make sure that no grouping WBS element is assigned to another grouping
WBS element, which itself is assigned to the first grouping WBS element
(also via several steps).

Error message extract from SAP system. Copyright SAP SE.