PPR selects invoices of other operating units

Hi Team,

I am encountering an issue with invoice selection during Payment Process Request process.

1. I am submitting PPR from US operating unit and UK invoices are being selected.

2. While submitting, I didn't pass any parameters viz: Payee group, Supplier, Invoice Batch, Payment method etc

3. Only the mandatory parameters were given viz: Exchange Rate, Disbursement account, Payment Document, Payment Process Profile

4. I specified 'All' with respective  Pay Groups , Legal Entities , Payment Currencies or Operating Units.

To my understanding, PPR has to select only US invoices.

I appreciate if some one can explain / assist on the above request.

Thanks in advance.