R47071 - Line Split when PO is received

We ordered 3 units in a purchase order (line 2.000) and received only 1 unit through EDI (R47071). In this case system splits one line (2.000) into two lines (2.000, 2.001), line 2.000 is having 2 units with status 400 next status (not received) and other line 2.001 is received with 1 unit and line is closed with next status 999.

Based on my understanding, I thought that there won’t be any split line and 1 unit would be received against that line 2.000 leaving the 2 units open against the same line 2.000 and the PO status for that line stays at 400/400.

Could you please confirm if my understanding is correct or system is behaving incorrectly due to some missing setups.