Changing OpenVPN from tun to tap or vice-versa breaks that instance
Where you have an OpenVPN client or server instance defined on tun and switch to tap, or vice-versa, the ovpnc*/ovpns* interface is retained from the previous configuration. ifconfig will error out with:
Oct 20 19:14:02 openvpn: FreeBSD ifconfig failed: external program exited with error status: 1 Oct 20 19:14:02 openvpn: Exiting due to fatal error
because the ifconfig it uses on a tap isn't valid on tun, or vice versa.
To work around, "ifconfig ovpncX destroy" (or ovpnsX), then edit and save the OpenVPN instance, which will re-create the tun/tap. Or reboot.