NextDNS Block Bypass Methods feature no longer works

I enabled Block Bypass Methods under Parental Controls in NextDNS and tested it with IPVanish a few months ago. IPVanish couldn't connect with this feature enabled. I enabled Block Bypass Methods to prevent my teenager from defeating Parental Controls in NextDNS. 

I challenged him today to defeat my Parental Controls (today was the first day I actually put him on the network that is using NextDNS for DNS servers and is blocked from being able to specify any non-NextDNS DNS servers. He fired up ProtonVPN and defeated my Parental Controls in literally 2 minutes. For a second I thought that Block Bypass Methods must not have been enabled under Parental Controls in the NextDNS account, but then I logged in and this setting  were enabled. ProtonVPN is a free VPN service in North America of which I haven't heard before at all. I just googled a review on this service, and it gets glowing reviews from multiple sources. It's a legit VPN service that is completely free and the speed I got on it was pretty good (200 Mbps down and close to 100 Mbps up). 

Then, I thought maybe ProtonVPN is doing something extraordinary to defeat the Block Bypass Methods setting enabled in NextDNS. So, I tried IPVanish (paid service), and it was able to connect. I know for a fact I had tested this before and consistently wasn't able to connect with IPVanish before. 

What happened and why is the Block Bypass Methods setting no longer blocking VPN services? This makes the entire NextDNS concept useless. My 13-year-old son defeated NextDNS Parental Controls in 2 minutes. 

Edit: I've just tried using CheckPoint Endpoint Protection VPN client to connect to my work. It connects no problem, whereas in the past, when I was on the Wi-Fi SSID configured for NextDNS filtering, I could not connect with the CheckPoint Endpoint Protection VPN. Something broke with the Block Bypass Methods feature in NextDNS in the past three months since I tested this last time.