setAcceptedMouseButtons not work properly

When

setAcceptedMouseButtons(Qt::LeftButton);

in your QQuickItem, and then

      void mousePressEvent(QMouseEvent *event)
      {
          qDebug()<<"mousePressEvent"<<event->button();
      }

We got mousePressEvent fired when both, left and right mouse button down.
I mean, first, you press left buttton - it fires (and its ok).
Than, you press right button - and it fires too (Qt::RightButton fired).

When click each mouse button separately - it works properly.

P.S. I have attached an example - click on black area in top (left , and while holding it - right or middle button).