Solution : https://service.sap.com/sap/support/notes/651795 (SAP Service marketplace login required)
Key words :
transaction mr1m 'add invoice, quantity field remains empty, database table ekbe, attached correction instruction, account assignment lines, account assignment screen, account assignment, field bmpng, initial screen', ekbe reason
Related Notes :
| 393189 | MIRO: Incorrect update of BPMNG -> DYNPRO_FIELD_CONVERSION |