The sample that I am testing with is attached. Run it with 6.6.x or 6.7.x. It's a ListView whose delegated item is the 3rd example here:
https://doc.qt.io/qt-6/qml-qtquick-draghandler.html#details
A Rectangle is added to show where the border is.

It runs perfectly on macOS. Each delegated item can be pressed on, and mouse can move inside it with correct Text being rendered and moved with cursor. With mouse button released, the history of transition of grab is 1->16->32->2.

But is not on iOS. One can only press on delegated item, but no response to pressed move. With mouse button released, the history of transition of grab is 1->2. But with grabPermissions: PointerHandler.TakeOverForbidden commented out, it works as expected on iOS.

So I am wondering if grabPermissions: PointerHandler.TakeOverForbidden is causing problem on iOS. Why is it handled differently on iOS?

One thing is that if the DragHandler is not put inside a contentItem: ItemDelegate, i.e. just run the 3rd sample (https://doc.qt.io/qt-6/qml-qtquick-draghandler.html#details) as it is, then it works on both macOS and iOS, regardless of grabPermissions.