Parental control- allow website

When I use parental controls on the iPad Air I added a website to

the Never allow list under content restriction. The issue is when the kids enter the website, it comes up with “Restricted site, you cannot browse....restricted” and then there is a button in blue that says “allow website”. The kids simply depress the allow websites and go to the website. How do I remove the “allow website”. I was trying to block YouTube. For some reason I also blocked roblox and this works and doesn’t come up with the allow website. Thanks