R12 AP Invoice Requestor name not available in LOV , Requestor employee of different BG

Hi

Our Client is on R12.1.3 and using financials and HRMS modules. For AP Invoices, approval hierarchy is in place. There are 2 Business Groups and 2 Operating units.  One employee is  booking invoices in both the Operating Units. However when he is  booking invoice in one OU , his name is not appearing in the LOV of Requestor name, however his name is there when he is booking the invoice in another OU.

I have already enabled Profile HR: Cross Business Group at user and responsibility level still it is not working

Am i missing on anything, how i can make this work