Callout standard NS still repond to queries while adv is enabled

Author: RebeccaTamachiro

src/content/docs/dns/foundation-dns/setup.mdx

@@ -17,6 +17,10 @@ import {
 
 Advanced nameservers included with [Foundation DNS](/dns/foundation-dns/) are an opt-in configuration.
 
+:::note
+After enabling advanced nameservers, standard nameservers still respond to DNS queries.
+:::
+
 ## Before you begin
 
 Before opting in for advanced nameservers, consider the following: