Solution : https://service.sap.com/sap/support/notes/1016185 (SAP Service marketplace login required)
Key words : 
00 solution background merging empty, -cumulative bearing time characteristic, >/4e<infocube> shadow table, storage parameter reason, 0calmonth oder 0fiscper, relevant processing step, exchange partition statement, empty shadow table, subsequent processing steps, execute repartitioning separately
Related Notes : 
       
| 1016184 | ORA repartitioning: Attaching partitions | 
| 1008833 | Supplementary SAP Note about repartitioning |