When trying to create a vmware host, on the 'Interface' tab, you can choose one of the dvPortGroup (distributed virtual port-group) exposed by the vcenter. This way one can choose the dvPortGroup related to the VLAN on which he wants to deploy my VM.

If someone makes a different choice instead of the default one (the first dvPortGroup in the list), the vm is created by the fog library with all the correct settings but the vNIC always remains disconnected.
Even trying to connect it by hand from the vsphere webclient, it gives a bad error: "Cannot connect ethernet0".

The (bad) workaround is to leave the first dvPortGroup selected by foreman without modifying it, submit the host creation and than modify the dvPort from the vsphere webclient once the vm has been created and power-on.

The use-case is described in this github PR: https://github.com/theforeman/foreman_bootdisk/pull/19#issuecomment-189899623

P.S.: I haven't the time to check if this bug is also present in the 1.10 branch.