Actually no. We talked about this in a thread a few months back. Unless you specifically tell openvpn to use your VPN’s DNS using scripts or set the DNS manually, the default OpenVPN action is to only tunnel the data.
When you request a URL, say google.com, the domain name is looked up at the DNS to get an IP, and a connection is made via the VPN, hiding the data but, not the request. If you are using the default, which is your ISP’s, then they can see you have gone into google.com, but can’t see what you did there.
So DNS leaking protection happens when you either use the scripts, or set your DNS to either Cloudflare, Google, or DNS over TLS.
Here are the scripts to set the DNS from the VPN provider: