Qt Designer writes duplicate verticalHeaderVisible entries in its *.ui file

When adding a QTableWidget to a window and setting its verticalHeaderVisible property, the Qt Designer writes that attribute twice into its *.ui file, i.e.:

<widget class="QTableWidget" name="myTableWidget">
...
<attribute name="verticalHeaderVisible">
<bool>false</bool>
</attribute>
<attribute name="verticalHeaderVisible">
<bool>false</bool>
</attribute>
...
</widget>

BTW, the UIC tool seems to accept that broken *.ui file and generates the corresponding attribute-setting code just once:

myTableWidget->verticalHeader()->setVisible(false);

The Designer of Qt 4.6.0 did not have that bug. The bug has been introduced in Qt 4.6.1 and persists in Qt 4.6.2. The bug might have been introduced while solving QTBUG-6505.