The OS X update I applied was the one that installed a host-based firewall. The update automatically turned on the FW and permitted all local servers that were configured to run, in my case SSH, with everything else being denied. The FW on the OS X box normally wouldn't see packets not destined for it until you put a nic in promisc mode such as what happens when you run EtherPeek. The OS X box's FW was getting hits from traffic denied by it's ACL and was sending TCP RSTs faster than hosts on the 'Net could respond. It did this for everything except SSH which it permitted (but higher up the IP stack it ignored because the IP packet was address to the local box).

This isn't in any way related to the problem at hand but it does demonstrate that weird things happen when devices in unusual places flood out all ports.