ROI Error: Receipt number must be unique. nnnnnnnn already exists.

With EBS 12.2.10 and database 19c (19.10.0.0.0) I want to import purchase orders (associated with LCM shipments) using Receiving Interface. If a transaction has been stuck because of some error(s), on next attempt to import it gives error: Error: Receipt number must be unique.

I updated transaction type as 'ADD' instead of 'NEW' but it did not work.

There is another observation. I find 2 lines in RCV_HEADERS_INTERFACE table however I inserted only 1. 2nd line found has been inserted with TEST_FLAG = 'Y' and TRANSACION_TYPE = 'NEW' which I believe inserted by system. What is the purpose of this 2nd line?