The OPPO and OnePlus OS builds are known to add Google's DNS to the configured DNS servers. This means that the phone always has a way to bypass any blocking from Pi-hole and use Google to resolve the domain. See this post.
The OPPO and OnePlus OS builds are known to add Google's DNS to the configured DNS servers. This means that the phone always has a way to bypass any blocking from Pi-hole and use Google to resolve the domain. See this post.