If you run Pi Hole, AdGuard Home, or any other network level adblocking services on your network, iOS 27's Connectivity Assist gets around these block lists in iOS applications.

That's because the cellular network it "Assists" with isnt blocked, and iOS treats your blocked traffic like it needs a workaround from the cell network.

To fix this, go to the settings for your specific Wi-Fi network and disable Connectivity Assist.