This looks to me like it is pretty much expected behaviour... There couldn't be more namservers appended to the list in resolv.conf as only the first three will ever be used by the libc resolver.
On the other hand, you may also mean that all DNS nameservers received from the VPN should be authoritative and used *instead* of the ones from the local network. In this case, could you confirm that the "Use this connection only for the resources on its network" checkbox, under IPv4 Preferences for the VPN connection is unchecked? Thanks!
This looks to me like it is pretty much expected behaviour... There couldn't be more namservers appended to the list in resolv.conf as only the first three will ever be used by the libc resolver.
On the other hand, you may also mean that all DNS nameservers received from the VPN should be authoritative and used *instead* of the ones from the local network. In this case, could you confirm that the "Use this connection only for the resources on its network" checkbox, under IPv4 Preferences for the VPN connection is unchecked? Thanks!