Diagnosis
Controlling object (cost center or order) &V1& is assigned to groupV2. you have already assigned a funds management (fm) accountassignment to group &V2&, which is valid for all controlling objectsfrom this group.

Procedure
If you want to assign a different FM account assignment to controllingobject &V1&, you must cancel the group assignment of controlling objectV1 to group v2 within controlling.