Inconsistency: installation &1 is allocated to contracts &3 and &4 on &2

What causes this issue?

Installation &v1& is allocated to contracts &v3& and &v4& on &v2&. This
data is inconsistent.

System Response

INCLUDE ISU_VERARB OBJECT DOKU ID TX

How to fix this error?

INCLUDE NA_SYSADMIN1 OBJECT DOKU ID TX

Procedure for System Administrators

Correct the entries in the EVER table.
Contact SAP.

Error message extract from SAP system. Copyright SAP SE.