Name resolution not refreshed after "power hibernate-restore" on OpenVPN client PCs

[robot-dot-win]

I have an OpenVPN server inside a LAN, which accesses the Internet via a NAT router:

    Server IP: 192.168.254.254
    Router IP: 18.143.175.x
    Server domain name: vpn.foo.com

Inside the LAN, the local DNS resolves vpn.foo.com to 192.168.254.254, while all outside DNSes resolve it to 18.143.175.x. The OpenVPN client configuration is like:

    client
    remote vpn.foo.com 81 tcp4

Note that inside the LAN, computers can also access 18.143.175.x:81-->192.168.254.254:81.

All OpenVPN clients can access each other(client-to-client) whether inside or outside the LAN. But in addition when a client is outside, the server will push a route to it via the "client-connect" script. Please see:

Server configuration file Server "client-connect" script Clent configuration file

Now is the problem: I have a laptop PC, after connected successfully with vpn.foo.com(18.143.175.x) ouside the LAN, directly set power hibernated. Then I moved the PC inside the LAN, having its power restored, and getting a LAN IP and DNS via DHCP. Now I hope OpenVPN could use the new DNS to resolve vpn.foo.com to 192.168.254.254, but it didn't, still using the old IP 18.143.175.x to make the connection. Thus the server still pushed the route to me, which made a confusion inside the LAN.