VPN Issues after 5.0 upgrade

First, a big thanks to all the Devs for your hard work and a smooth upgrade.

It may just be me, but after the upgrade nothing is getting blocked when I enable my VPN.
Everything was working great prior to the upgrade, whether the VPN was on or off. Now Pi-hole only blocks with the VPN off.
I'm using NordVPN, and I have the Pi-hole designated as my Custom DNS server, as it always was. Nothing else was changed besides the Pi-hole upgrade.

I would appreciate any pointers to get this working again.

VPN clients usually have a setting/option to force a/their DNS nameserver to prevent DNS leaks. Did you verify that this does not override Pi-hole as DNS nameserver?

Thanks MichaIng for your reply.
Then only option regarding DNS in NordVPN is an option called "Custom DNS", where I have always had the IP address of my Pi-hole. Two other options called "Obfuscated servers" and "Invisibility on LAN" are disabled. The platform for my NordVPN is Windows client. I would like to eventually install NordVPN in the same Raspberry Pi where the Pi-hole is installed, but that is a separate conversation. First I want to get everything working as it was prior to the upgrade. Again, none of the NordVPN settings have been changed in a while. The only change was the Pi-hole upgrade from v4 to v5.