Merlin has already coded a fix for the 'IPVanish' case for the next release.....
https://github.com/RMerl/asuswrt-merlin/commit/81909a28ec050d0f45613f6e63bdea45b34672d3
I can see 2 problems in the log file
May 10 15:42:01 rc_service: httpd 1767:notify_rc start_vpnclient1
May 10 15:42:02 kernel: tun: Universal TUN/TAP device driver, 1.6
May 10 15:42:02 kernel: tun: (C) 1999-2004 Max Krasnyansky <maxk@qualcomm.com>
May 10 15:42:03 openvpn[3792]: DEPRECATED OPTION: --tls-remote, please update your configuration
May 10 15:42:03 openvpn[3792]: OpenVPN 2.3.6 arm-unknown-linux-gnu [SSL (OpenSSL)] [LZO] [EPOLL] [MH] [IPv6] built on Apr 26 2015
May 10 15:42:03 openvpn[3792]: library versions: OpenSSL 1.0.0r 19 Mar 2015, LZO 2.08
May 10 15:42:03 openvpn[3792]: NOTE: the current --script-security setting may allow this configuration to call user-defined scripts
May 10 15:42:03 openvpn[3792]: Socket Buffers: R=[122880->131072] S=[122880->131072]
May 10 15:42:03 openvpn[3793]: UDPv4 link local: [undef]
May 10 15:42:03 openvpn[3793]: UDPv4 link remote: [AF_INET]208.76.111.154:443
May 10 15:42:03 openvpn[3793]: TLS: Initial packet from [AF_INET]208.76.111.154:443, sid=9a44212e 75a94b20
May 10 15:42:03 openvpn[3793]: WARNING: this configuration may cache passwords in memory -- use the auth-nocache option to prevent this
May 10 15:42:04 openvpn[3793]: VERIFY OK: depth=1, /C=US/ST=FL/L=Winter_Park/O=IPVanish/OU=IPVanish_VPN/CN=IPVanish_CA/emailAddress=support@ipvanish.com
May 10 15:42:04 openvpn[3793]: VERIFY X509NAME OK: /C=US/ST=FL/L=Winter_Park/O=IPVanish/OU=IPVanish_VPN/CN=tor-c02.ipvanish.com/emailAddress=support@ipvanish.com
May 10 15:42:04 openvpn[3793]: VERIFY OK: depth=0, /C=US/ST=FL/L=Winter_Park/O=IPVanish/OU=IPVanish_VPN/CN=tor-c02.ipvanish.com/emailAddress=support@ipvanish.com
May 10 15:42:05 openvpn[3793]: Data Channel Encrypt: Cipher 'AES-256-CBC' initialized with 256 bit key
May 10 15:42:05 openvpn[3793]: Data Channel Encrypt: Using 256 bit message hash 'SHA256' for HMAC authentication
May 10 15:42:05 openvpn[3793]: Data Channel Decrypt: Cipher 'AES-256-CBC' initialized with 256 bit key
May 10 15:42:05 openvpn[3793]: Data Channel Decrypt: Using 256 bit message hash 'SHA256' for HMAC authentication
May 10 15:42:05 openvpn[3793]: Control Channel: TLSv1, cipher TLSv1/SSLv3 DHE-RSA-AES256-SHA, 2048 bit RSA
May 10 15:42:05 openvpn[3793]: [tor-c02.ipvanish.com] Peer Connection Initiated with [AF_INET]208.76.111.154:443
May 10 15:42:07 openvpn[3793]: SENT CONTROL [tor-c02.ipvanish.com]: 'PUSH_REQUEST' (status=1)
May 10 15:42:07 openvpn[3793]: PUSH: Received control message: 'PUSH_REPLY,redirect-gateway def1 bypass-dhcp,dhcp-option DNS 198.18.0.1,dhcp-option DNS 198.18.0.2,rcvbuf 262144,explicit-exit-notify 5,route-gateway 172.20.32.1,topology subnet,ping 20,ping-restart 40,ifconfig 172.20.35.251 255.255.252.0'
May 10 15:42:07 openvpn[3793]: OPTIONS IMPORT: timers and/or timeouts modified
May 10 15:42:07 openvpn[3793]: OPTIONS IMPORT: explicit notify parm(s) modified
May 10 15:42:07 openvpn[3793]: OPTIONS IMPORT: --sndbuf/--rcvbuf options modified
May 10 15:42:07 openvpn[3793]: Socket Buffers: R=[131072->245760] S=[131072->131072]
May 10 15:42:07 openvpn[3793]: OPTIONS IMPORT: --ifconfig/up options modified
May 10 15:42:07 openvpn[3793]: OPTIONS IMPORT: route options modified
May 10 15:42:07 openvpn[3793]: OPTIONS IMPORT: route-related options modified
May 10 15:42:07 openvpn[3793]: OPTIONS IMPORT: --ip-win32 and/or --dhcp-option options modified
May 10 15:42:07 openvpn[3793]: TUN/TAP device tun11 opened
May 10 15:42:07 openvpn[3793]: TUN/TAP TX queue length set to 100
May 10 15:42:07 openvpn[3793]: do_ifconfig, tt->ipv6=0, tt->did_ifconfig_ipv6_setup=0
May 10 15:42:07 openvpn[3793]: /usr/sbin/ip link set dev tun11 up mtu 1500
May 10 15:42:07 openvpn[3793]: /usr/sbin/ip addr add dev tun11 172.20.35.251/22 broadcast 172.20.35.255
May 10 15:42:07 openvpn[3793]: updown.sh tun11 1500 1570 172.20.35.251 255.255.252.0 init
May 10 15:42:08 rc_service: service 3835:notify_rc updateresolv
May 10 15:42:08 dnsmasq[3587]: exiting on receipt of SIGTERM
May 10 15:42:08 dnsmasq[3843]: started, version 2.73rc1 cachesize 1500
May 10 15:42:08 dnsmasq[3843]: warning: interface ppp1* does not currently exist
May 10 15:42:08 dnsmasq[3843]: asynchronous logging enabled, queue limit is 5 messages
May 10 15:42:08 dnsmasq-dhcp[3843]: DHCP, IP range 192.168.1.2 -- 192.168.1.254, lease time 1d
May 10 15:42:08 dnsmasq[3843]: read /etc/hosts - 5 addresses
May 10 15:42:08 dnsmasq[3843]: using nameserver 8.8.4.4#53 for domain local
May 10 15:42:08 dnsmasq[3843]: using nameserver 8.8.8.8#53 for domain local
May 10 15:42:08 dnsmasq[3843]: using nameserver 8.8.4.4#53 for domain local
May 10 15:42:08 dnsmasq[3843]: using nameserver 8.8.8.8#53 for domain local
May 10 15:42:08 dnsmasq[3843]: using nameserver 198.18.0.1#53
May 10 15:42:08 dnsmasq[3843]: using nameserver 198.18.0.2#53
May 10 15:42:08 dnsmasq[3843]: using nameserver 8.8.8.8#53
May 10 15:42:08 dnsmasq[3843]: using nameserver 8.8.4.4#53
May 10 15:42:10 openvpn[3793]: Ignore conflicted routing rule: 208.76.111.154 255.255.255.255
May 10 15:42:10 openvpn[3793]: /usr/sbin/ip route add 0.0.0.0/1 via 172.20.32.1
May 10 15:42:10 openvpn[3793]: /usr/sbin/ip route add 128.0.0.0/1 via 172.20.32.1