Settlement unit &1 was assigned to more than one DME settlement unit

What causes this issue?

The settlement unit was assigned to multiple DME settlement units.
Therefore it is not possible to perform the service charge settlement,
for these reasons:
Each DME settlement unit can be settled separately, and the settlement
unit is thereby set to <ZK>settled</> status. When the other DME
settlement unit is settled, then the settlement unit already has
<ZK>settled</> status.
Cost assignment is no longer unique when the D-record is imported.

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

System Response

How to fix this error?

Assign the settlement unit to only one
<DS:GLOS.402A9CF0939C934D9589FF88FFCF26A3>DME settlement unit</>

Procedure for System Administrators

Error message extract from SAP system. Copyright SAP SE.