You are editing or updating outbound deliveries which refer to the same sales order at the same time. Error message MC601(with SOAP API) or VL045(with Application "Change Outbound Delivery") occurs indicate that sales order is locked by another user.
SAP S/4HANA Cloud
When working on a delivery document, the preceding document (sales order) must be locked to avoid database inconsistencies.
This is standard behavior.
The error message MC601 or VL045 will only show up temporarily as long as the update of one of the delivery documents is still running. Please avoid operate the deliveries at the same time with API or application.
MC601, VL045, requested object, locked, user, sales order, outbound delivery, picking, Odata API, change outbound delivery, API_OUTBOUND_DELIVERY_SRV;v=0002, MC/601, VL/045 , KBA , LE-SHP-DL , Delivery Processing , Problem