R12.2.7: Create Internal Orders does not pick any approved Internal Reqs for hours (4 to 20 hrs), an

In our Production (EBS R12.2.7), the Create Internal Orders runs for every OU, once every 15 minutes. But for some reason, from past week, it does not pick any approved Internal Requisitions. The program is completing normally, has no error messages. And the log file does not have any information on whether any records were picked or not.

And the strange thing is that it sometimes picks all records and processes. This maybe 4 hours to 20 hrs after the approval time of the IR.

We raised an SR, but no one seems to know what the issue is.  Please note that we had no issues with it 10 days back.