Google last released Android N Developer Preview 4 to those enrolled into Android Beta program. The update however brought one controversial change in the way the Quick toggles in Notification Center like WiFi/ Bluetooth/Mobile Data behave. These toggle icons in action center now open the settings on tapping and doesn’t toggle it on / off. You can watch this change in action by clicking here.
Since it was undesirable change for many, Google has now confirmed fixing and reverting WiFi / Bluetooth toggle behavior to its original state and has promised it to be available in a future release. But Mobile Data toggle still remains to be unchanged and will open settings page on tapping, it seems.
Android N DP4 coverage Android N Dev Preview 4 Changelog (Official & Unreported) Android N Dev Preview 4 Hands-on: Changes Demo & Impressions