Solution : https://service.sap.com/sap/support/notes/83531 (SAP Service marketplace login required)
Key words : 
additional key words classificationvaluationmultiple valuesmultiple classificationassignmentvaluation comparisonvalue comparison, inherited characteristics, prerequisites solution, advance correction, classification
Related Notes : 
       
| 83534 | Inconsistency message for multiple classification | 
| 79308 | Check for identical classif. with multiple classif. | 
| 79208 | Check for identical valuation during classification | 
| 78308 | Classification during value comparison | 
| 73973 | Error message for identical classification |