Recently a second interface has started to be added when I select a compute profile, giving my new host two. The first remains as the primary/provision interface but with the default settings, while the new interface is the one from the compute profile with the right compute/VM settings.

This seems to be fine on 1.8-stable, just a problem on develop.

My compute attributes (vm_attrs) from the console:

{"cpus"=>"2", "memory"=>"1073741824", "nics_attributes"=>{"new_nics"=>{"type"=>"bridge", "_delete"=>"", "bridge"=>"em1", "model"=>"virtio"}, "0"=>{"type"=>"network", "_delete"=>"", "network"=>"default", "model"=>"virtio"}}, "volumes_attributes"=>{"new_volumes"=>{"pool_name"=>"default", "capacity"=>"10G", "allocation"=>"0G", "format_type"=>"raw", "_delete"=>""}, "0"=>{"pool_name"=>"default", "capacity"=>"10G", "allocation"=>"0G", "format_type"=>"qcow2", "_delete"=>""}}}

In the "interfaces tab" screenshot, note the network name beneath each - the "NAT default" is correct and used to just be set on the first interface.