Custom rules are not working properly

When I add ads.youtube.com to the block list. Then I do nslookup:

> nslookup youtube.com
Server:  premium.dns.controld.com
Address:  76.76.2.XXX

Non-authoritative answer:
Name:    youtube.com
Addresses:  2404:6800:4005:802::200e
          172.217.24.238

> nslookup ads.youtube.com
Server:  premium.dns.controld.com
Address:  76.76.2.XXX

Non-authoritative answer:
Name:    ads.youtube.com
Addresses:  ::
          0.0.0.0

> nslookup www.youtube.com
Server:  premium.dns.controld.com
Address:  76.76.2.XXX

Non-authoritative answer:
Name:    www.youtube.com
Addresses:  ::
          0.0.0.0

> nslookup accounts.youtube.com
Server:  premium.dns.controld.com
Address:  76.76.2.XXX

Non-authoritative answer:
Name:    accounts.youtube.com
Addresses:  ::
          0.0.0.0

I just added ads.youtube.com to the block list. However, all subdomains of youtube.com will also be blocked.

Then I tried disabling all rules related to the youtube.com domain then ipconfig /flushdns. But when I execute nslookup again, the results are the same as above.

I tried completely removing the rules related to youtube.com, then tried again:

> nslookup youtube.com
Server:  premium.dns.controld.com
Address:  76.76.2.XXX

Non-authoritative answer:
Name:    youtube.com
Addresses:  2404:6800:4005:802::200e
          172.217.24.238

> nslookup ads.youtube.com
Server:  premium.dns.controld.com
Address:  76.76.2.XXX

Non-authoritative answer:
Name:    ads.youtube.com
Addresses:  ::
          0.0.0.0

> nslookup www.youtube.com
Server:  premium.dns.controld.com
Address:  76.76.2.XXX

Non-authoritative answer:
Name:    youtube-ui.l.google.com
Addresses:  2404:6800:4005:820::200e
          2404:6800:4005:81d::200e
          2404:6800:4005:800::200e
          2404:6800:4005:801::200e
          142.251.220.78
          142.250.204.142
          172.217.31.14
          142.251.220.46
          142.251.222.206
          172.217.24.78
          142.250.204.46
          216.58.200.238
          142.250.204.78
          142.250.66.46
          142.251.220.110
          142.250.204.110
          216.58.203.78
          142.251.130.14
          142.250.199.78
          142.251.220.14
Aliases:  www.youtube.com

> nslookup accounts.youtube.com
Server:  premium.dns.controld.com
Address:  76.76.2.XXX

Non-authoritative answer:
Name:    accounts.youtube.com
Addresses:  ::
          0.0.0.0

Only youtube.com and www.youtube.com return results, other subdomains are still blocked.

I only enabled the custom filter, not any other filters/services, but it was blocking incorrectly.