Broken painting of empty item views with QGraphicsOpacityEffect applied

Looks like painting of empty item views with QGraphicsOpacityEffect is broken. When at least one item is added, it is all ok. In more complex applications it causes a significant elevation of CPU/GPU usage. I know, that Qt 5.9.6 was not affected by this bug.

Appears that this issue have a workaround. We can add a header and set it's height to 0 to "hide" it. The main thing is that item view must have something drawn inside, to bring it's painting loop back to normal and do not repaint recursively.

ui->treeWidget->setHeaderHidden( false );
QHeaderView *headerView = ui->treeWidget->header();
headerView->setSectionsClickable( false );
headerView->setSectionsMovable( false );
headerView->setSectionResizeMode( QHeaderView::Fixed );
headerView->setMaximumHeight( 0 );