Pi-Hole removing filtering ads.
-operating system Raspian latest version.
-hardware]_Raspberry Pi 4 8gb. Firefox internet browser.
Actual Behaviour:
Works with other devices on our home network. But when surfing internet with rasperry pi, pi hole seems not to filter traffic. Confirmed looking at same page with computer and Rasperry pi.
Assuming you are referring to the same RPi that runs Pi-hole, your observation is to be expected. As announced for Pi-hole 5, Pi-hole does not interfere with its host system's DNS resolution anymore.
I could not explain motivations for picking a DNS server any better than jfb has done already.
Have a read and decide for yourself how you'd want to change your RPi's DNS server.