Solution : https://service.sap.com/sap/support/notes/574341 (SAP Service marketplace login required)
Key words : 
automatic time conversion reason, automatic time conversion, fiscal year variant, time-reference characteristic, time characteristics, -cumulative cubes, terms update, prerequisites, calculated, information
Related Notes : 
       
| 571464 | Error while activating the update rules; G_S_IS | 
| 569766 | Identical values with time characteristics in non-cumulative | 
| 567740 | Initial values when updating into stock cubes | 
| 554380 | Error when updating stock cubes | 
| 542340 | Update in non-cumulative cubes |