We have an serialized inventory item showing quantity 27 On Order. We have had 5 purchase orders totally Qty 25 in total, Qty 8 now Fully Billed, leaving Qty 17 on open purchase orders. Other than POs are there other transactions which can impact the Item's Qty on Order?

Transfer orders (regular and intercompany) and work orders (if it's an assembly but it seems to be an inventory anyway)?

@Luis yes. no TransOrds ever on this one. 13 units assembled by WO and now all Built status. I also reviewed all the open and completed POs in case someone had done something funky with a IR or not Billed all the lines.