Diagnosis
In your settings for the checks, you have specified that the assignmentof object type &V1& to the billing element must be unique - that is,there may be only one object of this type for each billing element.
However, the system found more than one object of this type.

Procedure
You can find out what objects were found from this message and thosebefore and/or after it.
If you position the cursor on one of the messages, you can branch tothe matching object in display or change mode.