TouchEvent in Flickable and its children

[Trian]

I have a Flickable qml which contains a list of cpp qquickitems. Qquickitem handle its own touch event.
Flickable handles vertical touch for scrolling ( flickableDirection: Flickable.VerticalFlick).
Its children, qquickitems, handles touch pan in x direction and pinch.

I notice sometimes TouchEnd event is handed in Flickable while other times, it is handled in qquickitem.
This is more noticable when my finger first moves in x direction and then in y direction. I think when moving in x direction, touch event is handled by qquickitem; without lifting finger, moving in y direction, touch event is handled by Flickable. Now, Lifting finger, TouchEnd event is handled and accepted by Flickable. As a result, qquickitem would not receive TouchEnd event.