Log entries on the pfSense, showing it's clearly getting the Ping response back; I'm just not sure how to find out what it's doing with it after that. I've removed a few repetetive entries but nothing that seems pertinent.
May 4 14:57:21 charon 46137 16[JOB] got event, queuing job for execution
May 4 14:57:21 charon 46137 16[JOB] next event in 88ms, waiting
May 4 14:57:21 charon 46137 16[JOB] got event, queuing job for execution
May 4 14:57:21 charon 46137 16[JOB] next event in 5s 890ms, waiting
May 4 14:57:21 charon 46137 09[IKE] <con2|12> sending DPD request
May 4 14:57:21 charon 46137 09[IKE] <con2|12> queueing IKE_DPD task
May 4 14:57:21 charon 46137 09[IKE] <con2|12> activating new tasks
May 4 14:57:21 charon 46137 09[IKE] <con2|12> activating IKE_DPD task
May 4 14:57:21 charon 46137 16[JOB] next event in 5s 890ms, waiting
May 4 14:57:21 charon 46137 09[ENC] <con2|12> order payloads in message
May 4 14:57:21 charon 46137 09[ENC] <con2|12> generating INFORMATIONAL request 1585 [ ]
May 4 14:57:21 charon 46137 09[ENC] <con2|12> generating payload of type HEADER
May 4 14:57:21 charon 46137 09[ENC] <con2|12> generating ENCRYPTED payload finished
May 4 14:57:21 charon 46137 09[NET] <con2|12> sending packet: from X.X.X.X[500] to Y.Y.Y.Y[500] (80 bytes)
May 4 14:57:21 charon 46137 04[NET] sending packet: from X.X.X.X[500] to Y.Y.Y.Y[500]
May 4 14:57:21 charon 46137 16[JOB] next event in 3s 999ms, waiting
May 4 14:57:21 charon 46137 02[NET] received packet => 80 bytes @ 0x7fffdfdfa5f0
May 4 14:57:21 charon 46137 02[NET] received packet: from Y.Y.Y.Y[500] to X.X.X.X[500]
May 4 14:57:21 charon 46137 02[ENC] parsing header of message
May 4 14:57:21 charon 46137 02[ENC] parsed a INFORMATIONAL response header
May 4 14:57:21 charon 46137 02[NET] waiting for data on sockets
May 4 14:57:21 charon 46137 09[NET] <con2|12> received packet: from Y.Y.Y.Y[500] to X.X.X.X[500] (80 bytes)
May 4 14:57:21 charon 46137 09[ENC] <con2|12> parsing body of message, first payload is ENCRYPTED
May 4 14:57:21 charon 46137 09[ENC] <con2|12> starting parsing a ENCRYPTED payload
May 4 14:57:21 charon 46137 09[ENC] <con2|12> parsing ENCRYPTED payload, 52 bytes left
May 4 14:57:21 charon 46137 09[ENC] <con2|12> parsing ENCRYPTED payload finished
May 4 14:57:21 charon 46137 09[ENC] <con2|12> verifying payload of type ENCRYPTED
May 4 14:57:21 charon 46137 09[ENC] <con2|12> ENCRYPTED payload verified, adding to payload list
May 4 14:57:21 charon 46137 09[ENC] <con2|12> ENCRYPTED payload found, stop parsing
May 4 14:57:21 charon 46137 09[ENC] <con2|12> process payload of type ENCRYPTED
May 4 14:57:21 charon 46137 09[ENC] <con2|12> found an encrypted payload
May 4 14:57:21 charon 46137 09[ENC] <con2|12> parsed content of encrypted payload
May 4 14:57:21 charon 46137 09[ENC] <con2|12> verifying message structure
May 4 14:57:21 charon 46137 09[ENC] <con2|12> parsed INFORMATIONAL response 1585 [ ]
May 4 14:57:21 charon 46137 09[IKE] <con2|12> activating new tasks
May 4 14:57:21 charon 46137 09[IKE] <con2|12> nothing to initiate