GL 750m travel router

Hello
I am a bit confused how to prevented such a unwanted action ( I am using a VPN on a daily basis to connect to my resources.)

MY ISP > traffic to GL router > Wireguard VPN → VPN IP

I noticed that sometimes my VPN stopped working, and I didn’t even notice, and I am connecting to resources with my ISP provider.
MY ISP IP> traffic to GL router > Wireguard VPN ( stop working without noticed) → MY ISP IP is visible

there is anyway i can prevented that?

Thank you