Solution : https://service.sap.com/sap/support/notes/1500161 (SAP Service marketplace login required)
Summary : 
      A BW query leveraging a LEFT OUTER join on an InfoSet might fail with the error "Illegal selection by InfoObject from outer join table". This response isn't due to a program bug but stems from using exclusion conditions in LEFT OUTER Join queries, which lead to potential data inconsistencies. SAP Note 1435772 implemented a fail-safe to curb such issues. To override this safety mechanism, adjust the RSADMIN parameter EXCL_FOR_OUTER_JOIN to 'X' via the SAP_RSADMIN_MAINTAIN report.
Key words : 
left outer join terminates, left outer join, outer join table, left-outer field, bw query defined, undefined query statuses, rsadmin parameter excl_for_outer_join, illegal selection, terms infoset, excluding reason
Related Notes : 
       
| 1500078 | SAPBWNews NW BW 7.02 ABAP SP06 | 
| 1471463 | SAPBWNews NW BW 7.01 ABAP SP08 | 
| 1468668 | SAPBWNews NW7.0 BW ABAP Support Package 25 | 
| 1435772 | InfoSet using left outer join and EXCLUDING conditions | 
| 1392433 | SAPBINews NW7.11 BW ABAP Support Package 05 |