Discussion on the ML confirmed that these *do* wait (implicitly) on network-online.target. If you do "systemctl show -p Wants -p After mnt-server.mount" you should see
Wants=network-online.target system.slice After=remote-fs-pre.target network-online.target network.target system.slice -.mount [...]
So this is merely a duplicate of bug 1430280.
Discussion on the ML confirmed that these *do* wait (implicitly) on network- online. target. If you do "systemctl show -p Wants -p After mnt-server.mount" you should see
Wants=network- online. target system.slice fs-pre. target network- online. target network.target system.slice -.mount [...]
After=remote-
So this is merely a duplicate of bug 1430280.