Phantom IP's/ Route after interface changes

[hgerding]

Old firewall IP address "route" shows up on the WAN link but only in the routing table even though the IP is no longer configured.

System --> Route --> Status
ipv4   192.168.100.1   link#5   UHS   NaN   1500   em0   WAN

The route/ link#5 keeps coming back.

I had an issue where I was repurposing a firewall from one building to another for a client and the old client firewall was unreachable on the old internal address. (I need that IP for an in-building link)

In the process of re-purposing it, I just changed the configuration instead of reinstalling it (Which may have been a mistake.

So I had
LAN --> igb3 (Old IP 192.168.100.1/24)
after the move, I was no longer using igb3 for LAN
Not configured --> igb3
It showed up in the arp table for igb3 (Which would imply it is on a different machine which it is not)
Statically setting a different IP on igb3 got rid of the ARP address

Statically setting the IP gets rid of it for a while. But I need the WAN interface to be set to DHCP.

I have searched/ Grep'd the hard drive and looked at the config.xml but cannot find 192.168.100.1 and looked at every webpage (or tried to) and did not find it.

Any suggestions?