Recently i started to use a second dynamic dns and i got problem.
I have two addresses on one account at freedns.
They point at WAN and OPT1.
I use the same username but two different passwords for them.
When a update is made in pfsense to reflect a new ip on either of them both dnses are set to the same ip.
When i check the pfsense config i see that both have the same update password set to them and thats why both get the same ip.
So pfsense messes up here.