RHEL5 system with NIC bonding and bnx2 stops responding to "arp who has" (machine unreachable, "destination host unreachable")

Issue

• The machine becomes unreachable on it's own subnet. The failure occurs at "arp who has" (never responded, so we are not able to find out which mac address we should send the traffic for). Further investigation shows that the "arp who has" is being dropped by the network card, before it reaches the kernel stack.

• We can no longer ping our system, but when I issue a packet capture on the primary interface, the ping request is successful.