pfSense

Not able to replicate just yet.

I have a static gateway on my LAN for the Cisco 1811 and I can add a monitor IP just fine on that?

[3] => Array
                (
                    [interface] => lan
                    [gateway] => 192.168.11.248
                    [name] => CISCO4
                    [weight] => 1
                    [ipprotocol] => inet
                    [interval] => 
                    [descr] => Cisco 1811
                    [monitor] => 192.168.14.33
                )

Gitsync from today. Need to look further I guess.

Added a different monitor IP on my WAN gateway entry (DHCP) and it works? Also adds the route for the monitor IP.
Changed the monitor IP on my WAN gateway entry, worked.

edit a static IPv4 gateway, blank out the monitor IP, save. Edit it again, try to put in a monitor IP, and it does this.

I saw room for improvement regardless, we now have a ipprotocol tag so we don't have to guess the address family. Just checked in a fix that I hope prevents the bogus message.