The firmware version of my GL-MT300N-V2 is 3.025.
The GL.iNet Admin Panel says:
If you enabled VPN but the VPN cannot connect to its server, there will be NO Internet.
When you change server while VPN is connected, VPN will not be leaked.
I’ve made a following script on a Raspberry PI sitting behind the GL-MT300N-V2 (on the LAN side of it):
while :; do date ; curl ifconfig.me ; printf "\n"; sleep 1; done |tee /home/pi/iplog
The output shows that while the GL-MT300N-V2 lost its VPN connection three curl requests (one second from another each) from the Raspberry PI to ifconfig.me have shown my actual provider’s IP before new VPN IPs got showing again.