MessageDialog won't load in a static Qt Build

The app won't load when using a static build of Qt that uses MessageDialog

It complains it can't find DefaultMessageDialog.qml; if I try to add that to the import path, then it can't find another qml file and so on.

If I comment the MessageDialog out and leave only the button, all works fine.

Code to repro:

import QtQuick 2.6
import QtQuick.Window 2.2
import QtQuick.Controls 1.5
import QtQuick.Dialogs 1.2

Window {
 visible: true
 width: 640
 height: 480
 title: qsTr("Hello World")

 Button {
   text: "Click me"
   onClicked: dialogErrorMessage.open();
 }

 MessageDialog {
  id: dialogErrorMessage
  title: qsTr("Access Denied")
  icon: StandardIcon.Critical
  text: qsTr("The password you entered is incorrect.")
  standardButtons: StandardButton.Ok
 }
}

Output:

qrc:/main.qml:17 Type MessageDialog unavailable
qrc:/qt-project.org/imports/QtQuick/Dialogs/DefaultMessageDialog.qml:-1 No such file or directory

Qt was compiled with :

-debug-and-release -commercial -confirm-license -static -force-debug-info -optimized-tools -mp -no-icu -ltcg -opengl desktop -nomake examples -no-angle -no-sse3 -no-ssse3 -no-sse4.1 -no-sse4.2 -no-avx -no-avx2 -skip qtscript -skip qt3d -skip qtwebengine -skip qtwebchannel -skip qtlocation -skip qtserialport -skip qtquickcontrols2 -skip qtmultimedia -skip qtsensors -skip qtserialbus -skip qtwebview -skip qtxmlpatterns -skip qtwebsockets -skip qtconnectivity

This only happens when running the above minimum code in Release mode. Debug builds work fine.