The latest info / update is that we have tracked the locking to ADR3MAS messages (aka BusinessPartnerERPContactAddressReplicationIn messages) in contention with itself.
The DEBMAS, ADRMAS all go in fine as part of the intial data load.
But when the ADR3MAS (ContactAddress web service messages) come in, they eventually get into Appliation Error status and the Error Text is "Operation not possible; business document locked".
Appreciate any tips.