[arch-general] openvpn-client@ takes long time to start

After a reboot, the first openvpn-client@ instance I try to start takes almost exactly two minutes to start. The instances before that one start just fine in a few seconds. When that happens, I can see from journalctl that the client actually starts in the first few seconds after the systemctl command. But then, the command doesn't terminate for two more minutes (with no further journal entries). Has anyone seen this before? What could it be? Riccardo