Hi,
Your question is related to FreePBX/Elastix and not FOP2 itself. Elastix performs some modifications over FreePBX recordings, and it does not use the latest FreePBX available. You should be posting this question into Elastix forums to get a proper or more incumbent response. If you configured FreePBX to record all calls, you might have the recording on /var/spool/asterisk/monitor, but depending on how you actually start the recording, it might be set to only record BRIDGED calls (phone to phone calls so to speak), that means that calls to an application, like IVR, is not recorded. But I do not know if FreePBX/Elastix use that option for Monitor/MixMonitor, or not.
Best regards,