Podman ftw!

Sounds like the DNS TTL (Time to Live) is set extremely low, preventing clients caching the record. Each time your browser makes a request (such as updating the graphs), it’s submitting a new DNS query each time.

According to this post, this is intentional behaviour for PiHole to support situations where you change a domain from the block to allowed. The same post also references the necessary file modifications, should you wish to extend the TTL regardless.

The only downside you’ll notice is a delay after whitlisting a domain, and it actually being unblocked. You’ll need to wait for the TTL to expire. Setting it to something like 15 minutes would be a reasonable compromise.