Can be reproduced with tests/manual/pointer/pinchHandler.qml : you can use a 3-finger pinch to manipulate PinchHandlers that are labeled as 2-finger pinch (although those don't have maximumPointCount declared), and you can't manipulate a 3-finger PinchHandler with an actual 3-finger pinch gesture. Being able to tell the number of fingers is a new feature on Wayland in 6.2, so we should now use QNativeGestureEvent::fingerCount() here:

bool QQuickPinchHandler::wantsPointerEvent(QPointerEvent *event)
{
    if (!QQuickMultiPointHandler::wantsPointerEvent(event))
        return false;

#if QT_CONFIG(gestures)
    if (event->type() == QEvent::NativeGesture) {
        const auto gesture = static_cast<const QNativeGestureEvent *>(event);
        if (minimumPointCount() == 2) { // <---- that was an assumption