Enabling manual outbound NAT broke firewall

[Gob]

Hi
Trying to resolve some VoIP issues we switched one of our remote pfSense boxes (v2-1-3 amd64) to Manual Outbound NAT so that we could enable static port.
The auto rules were not created for some reason so we manually added the following mappings (NAT.PNG):

Upon applying the changes we noticed a high amount of traffic on the WAN interface and then lost connection to the box.
We got somebody local to reboot the box but the same thing happened.
We were able to talk somebody through switching back to Automatic NAT and everything reverted to a normal state again.

After further examination of the RRD graphs it looks like there is some sort of loop going on within the pfSense box.
Attached are the graphs for WAN, WAN2, LAN & SYSTEM. The DMZ interface didn't have any traffic on it.

Any suggestions on what is going on and how we can enable AON ?

Cheers