OpenVPN routing is broken in some cases on FreeBSD 11 after r293159
This patch was obtained from OpenVPN mailing list:
https://www.mail-archive.com/openvpn-devel@lists.sourceforge.net/msg12950.html
It was previously applied on pfSense ports tree and tested by pfSense users, who
confirmed it fixes the issues. Here you can see more details:
https://community.openvpn.net/openvpn/ticket/425#comment:14
https://redmine.pfsense.org/issues/6883