The ipaddress fact isn't reliable in what IP address it actually picks. If several VLANs are available, it picks the IP of the VLAN with the lowest number, which might not be the correct one.
To fix this, I have created a custom fact that looks at the default route and picks the IP of the interface used there, which is most likely correct in every case ever.

However, foreman doesn't care about this of course, and still uses the IP of the ipaddress fact to update IP's, which leads to a bunch of servers having wrong IP's in foreman in our environment.

I would like to be able to resolve this by choosing which fact foreman looks at to determine the IP of a host.