Hi,
Is there any chances traffic is being load balanced and some return packets for that session is assymetric:
Aug 1 11:56:07 11:56:06.291369:CID-1:RT:Conflict session (365626) is VALID state Aug 1 11:56:07 11:56:06.291369:CID-1:RT: packet dropped, failed to install nsp2 Aug 1 11:56:07 11:56:06.291369:CID-1:RT:failed to install nsp2
Cheers,
Ashvin