Have you had past success with having a product instance name equal two different technical systems?
I see you created SXP and have SX1 and PX1 tied to it, within the LMDB.
I have seen items product instances using the same 3 characters as the technical instance, I think the LMDB is allowing this; and SMSY is the issue; based on your screenshot, if you can find SXP then my thought process would probably change.
Can you verify that other MOpz transactions work without issue?