Solution : https://service.sap.com/sap/support/notes/1237075 (SAP Service marketplace login required)
Key words : 
symptom /sapapo/om_upgr_tstr_check, system incorrectly reports, terms upgrade reason, time stream, problem occurs, solution implement, attached corrections, prerequisites, maintained
Related Notes : 
       
| 1257293 | Notes regarding resource time stream, relevant for upgrade | 
| 1065366 | /SAPAPO/OM_LC_UPGRADE_51: Problems during the upgrade | 
| 1008187 | Composite note for problems w/ /SAPAPO/OM_LC_DOWNLOAD_UPLOAD |