nullifi, have you ever figured this out?
We have been struggling with sporadic failovers (master demotes itself) for over two years now on one cluster.
This never happens on any other cluster, just this particular one, and we can't seem to find out why. Both hosts run VMWare 4.1 with all MAS forgery, promiscuous mode, this NetReverseFiltering = 1. None of the other PFSense clusters on the two VMWares have this problem, just this one, so I think this may be PFSense/Config related rather than Layer 2, as the other boxes share the vswitch on VMWare.
Also, on the CARP status page, clicking "Disable" then "Enable" repairs it until it demotes itself again.
Any ideas?