Thanks for the reply, Derelict.
Sorry for my slow reply. I went in for surgery, and am just back on my feet again.
It is indeed unusual. I can see the connection in the state table of the master node, with TIME_WAIT:TIME_WAIT, and 9/4 packets, but the browser tells me the connection was reset, and indeed telnet to the management port is denied as well. ARP of the pfSense VIP is correct on the pinging machine, and ARP of the pinging machine is correct on the pfSense box. It seems like pfSense is blocking the connections, even though it's been told to allow them through (my allow rule uses an alias that includes the VIP and both real IPs of the pfSense boxes). Very, very strange.
I'll walk through the Network Connectivity process and see if it turns up anything.