Currently, is retrieved by default only from the device with the
default route. This is done so that in presence of multiple
connections the choice is deterministic.
However, this limitation seems confusing for users, that expect to get
an hostname even for non-default devices. Change the default and allow
any device to obtain the hostname.
Note that when there is a default route, NM still prefers that device
and so the behavior doesn't change.
The only change in behavior is that when there is no default route and
the machine doesn't have a static hostname, NM will try to get
hostname from DHCP or reverse DNS.
https://bugzilla.redhat.com/show_bug.cgi?id=1766944