Solution : https://service.sap.com/sap/support/notes/593368 (SAP Service marketplace login required)
Key words : 
transaction 'maintain gr/ir clearing account', account maintenance documents, account maintenance, transaction mr21, system distributes, system outputs, terms ckmlgrir, valuated stock, program error, support package
Related Notes : 
       
| 568931 | MR11: Prev.month's invent.value is zero for act. mat.ledger | 
| 509823 | MR11: C+048 after posting to a prior period | 
| 508085 | MR11: Incorrect posting date of revaluation posting | 
| 505741 | MR11: Error M7 308 when posting to a prior period | 
| 437613 | MR11: Clearing IR surplus with partial stock valuated mater | 
| 392663 | MR11: Coll. note: Inconsist. between MM and FI in act maint. |