SAP Message RSAN_WB102 - The field assignment for unknown source field &1 is being deleted

Diagnosis
A field assignment exists for the source field &V1&. However, thisfield is not found in the source structure.
This status can occur when fields have been deleted from the sourcestructure (because the query definition has been changed).

System Response
The system deletes the invalid field assignment.

Procedure
Leave the dialog box for field assignment maintenance by confirming itand save the corrected field assignments.