Why can the connection change from VPN to main?

Question

VPN

There is a problem on Windows 10 - sometimes the system stops using an active connection to the VPN service. The VPN client program writes that everything is connected, and in the list of networks, respectively, there are 2 networks - an ordinary one and a VPN, both in the "Connected" status. But for some reason, a normal connection is used, i.e. traffic does not go through the VPN, but as usual. What could be the problem?
An important detail: this never happens immediately after connecting to the VPN, the change of the priority adapter occurs already in the process of using the system, 7-8 hours after connecting to the network. VPN service support advises replacing DNS servers with OpenDNS, but it seems to me that if DNS spoofing took place, it would be visible immediately after connecting. I'm right?

Answer 1

Are you using a personal server on which VPN is up or using a VPN service?