O Batch in Use

Hi , Need some advise on an issue we have in Production.

We use Middleware. The process we follow is:

Third party vendor sends/uploads a ASN(Goods shipped for PO's) information file into a FTP folder.

Middleware picks up that file every night and triggers the BSFN(xpiProcessInboundReceipt).

Then the PO receipts will take place and at the same time O batches are created.

But the problem is lot of these O batches are going into in USE status. We need your advise on what could be the reason for this and which are the points where we can check to find the root cause.