Steps to reproduce:
Take the example quick/quickwidgets/quickwidget as base.
In rotatingsquare.qml, add import QtQuick.Controls 2.1 to the top, then the following inside the root Rectangle:
Run program, click on the button with touchscreen and with mouse
Expected: "Button is pressed" will be printed on stdout for both
Actual: "Button is pressed" is printed only for mouse click, but not on touch click
You can also try a SwipeView. Swiping with touchscreen will fail to swipe pages.
This is a regression in 5.9.4. The same works on 5.9.3.
I suspect it could be a result of the fix to
QTBUG-64241, but I may be completely wrong.