SAP Message UGMD328 - Error while writing hierarchies in system &3 - see long text

Diagnosis
Errors occurred when writing hierarchies for characteristic &v2&(technical name &v1&) to system &v3&.

System Response
Processing is continued.

Procedure
Analyse the following messages to explain the reason for the errors. Ifnecessary, manually synchronize the hierarchies of characteristic &v1&.