From "Active Calls/Events" and "Selected Variables" you should be able to identify IDOCs which cause the issueYou may then check the IDOC status and reprocess using BD87 if not completed.
In segment type E1EDKA1 the partner number is preceded by the "Partner function (e.g. sold-to party, ship-to party, ...)"PARVW EDI3035_APARTN PARTNERSo maybe this prefix 'A00' simply is the Partner function ?