1. New Project using Application (Qt Quick) - Empty
2. Replace main.qml contents like below.

import QtQuick 2.12
import QtQuick.Controls
import QtQuick.Window 2.12

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

    Button {
        text: "Button"
    }
}

3. Build release
4. ./macdeployqt macbug.app -qmldir=<project-location>
5. Run ./macbug.app -> crash

Now try removing 'import QtQuick.Controls' and the Button, it not crash with macdeployqt.

Everything works fine during development.