This issue is related to QTBUG-116442. TL;DR, I think fixing QTBUG-116442 may also fix this issue.

In the attached example in QTBUG-116442, if run against Qt 6.5.1, the MouseArea will not emit the clicked signal for its second click (the third click in the testcase). The reason for this is a behavior change in QQuickItem:

void QQuickItem::mouseDoubleClickEvent(QMouseEvent *event)
{
    event->ignore(); // <== this was introduced
}

This ignore causes QQuickDeliveryAgent to cancel mouse event synthesis:

                    QCoreApplication::sendEvent(item, &mouseDoubleClick);
                    event.setAccepted(mouseDoubleClick.isAccepted());
                    if (!mouseDoubleClick.isAccepted())
                        cancelTouchMouseSynthesis(); // <== this happens
                }

...And the consequence of this is that the cancel function sets "touchMouseId = -1" which prevents

        } else if (touchMouseDevice == device && p.id() == touchMouseId) {

which fails to send MouseButtonRelease which is why, it seems, the click isn't received.