Hi Atif,have you found the answer about the Case what the TAC said? I met the same problem that my customer has the idea as you gave above , would it indeed a good option?

Have you configed the "peer-gateway" option at the vPC ? I have the experience about that when used vPC in front of the F5 NLB device.Sent from Cisco Technical Support iPad App

what a great job, it helps me knowing much than before about the troubleshooting issue for the ASA!

appreciate for the work！

Have been waited too long