Group: definition of scrap exception WBS element &1 is incorrect

What causes this issue?

Definition of scrap exception WBS element &V1& is incorrect. This may be
because not all grouping WBS elements that have group-to-group transfer
between each other are entered on the selection screen for the pegging
report.

System Response

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

How to fix this error?

Run pegging with all groups (involved in group-to-group transfer)
together.

Procedure for System Administrators

Error message extract from SAP system. Copyright SAP SE.