Back Tap stop working on iPhone after an update

I had to turn off my back tap, restart device and then re-enable the setting to get it to work.

The “why?” questions are beat left for Apple.

As for one possible fix, select something else for back-tap (or nothing), force-restart (holding until the Apple logo, past any sliders), and then try enabling back-tap again.

It’s also possible that your phone hardware is no longer working with back-tap.

Make sure your battery health is above 80% and is operating as expected, as a swelling battery can cause all sorts of trouble.

The same thing happens to me with the iPhone Duo on both iOS 27.2 and 27.1.

When I assign certain actions (like turning on the flashlight) to Back Tap, they work just fine. However, when I assign actions like scrolling or Rotation Lock, nothing happens.

The weird thing is that when I enable the confirmation banner, it does appear. So the phone clearly detects the double or triple tap and displays the confirmation banner, but it doesn't actually perform the scrolling or Rotation Lock action.

Other actions, like turning on the flashlight, work perfectly fine.

I'm not sure if this is an issue specific to the iPhone Duo. Everything worked fine on my previous iPhone 17 Pro, but I wasn't running this version of iOS at the time.

Any ideas? Is anyone else using an iPhone Duo with iOS 27.2 able to get scrolling to work with Back Tap?