Solution : https://service.sap.com/sap/support/notes/553403 (SAP Service marketplace login required)
Key words :
'check planning area' switch, product allocation assignment check, incoming orders quantity, product allocation group, period end date, period start date, itab_duplicate_key runtime error, product allocation assignment, /sapapo/qttab table, /sapapo/lmsdp_bapisu05function module
Related Notes :
| 676128 | Product allocations: Product allocation assignment check |