IP Forwarding VS 0/0 causing LTM to respond for disabled Standard VS

We are currently doing the exact same VIP migrations from old to new. We created nodes and pools first and made sure all the fw rules were in order and then during the actual cut over deleted the old vips - sync and created the vips on the new boxes. I know this is not what you are doing or asking but thought I would get it out there.

Regarding why the virtuals would respond when you enable ip_fwd even when your apr is disabled ...do you think during your initial setup (before you figured out to disable arp and icmp) the arp requests are cached?