Various websites unreachable when OpenVPN simply enabled (not connected to)

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I am setting up a new OPNSense install and created a new OpenVPN server instance for a peer-to-peer network. When I simply enable the OpenVPN server instance (not connect to it from another site or anything, simply enable it on the main network), the main network begins to act strange, various sites and services become unreachable, but not all. As soon as I disable OpenVPN everything works fine. If I successfully visit a site that was previously unreachable while OpenVPN was disabled, then visit it again after it's re-enabled, that specific site suddenly become reachable again, but others that I haven't visited yet aren't. Pinging problematic sites while OpenVPN is enabled shows the proper IP, but the ping fails to actually reach the sites. Same with trace route.

I am surprised that simply enabling the OpenVPN service can have such effects on the host network. These sites aren't meant to be going through the vpn in the first place.

Any idea what's going on?

UPDATE:

I have traced the issue to a specific option in the OpenVPN config: "Verify Client Certificate". If this options is enabled, the aforementioned problems arise, if it is disabled, the network works fine. Any idea how/why that could be? These are just sites on the web from the host network, I am not trying to connect to the vpn from clients.