The Material style UI is looking bad when using software OpenGL rendering

I am using Qt5.9.2 and Qt Creator 4.4.1
installed from standard setup file "qt-opensource-windows-x86-5.9.2.exe"
(md5 862f6c276f3f466d253531778bddcfca)
My operating system is Windows 7 x64 sp 1.

Possibly I have some problems with my graphics card or driver because
all QML applications compliled for Windows are looking as you can see on
"Fuzzy.png" picture. All controls are fuzzy and sometimes transparent.
I resolved this problem by adding the following lines to my main.cpp file
just before the QGuiApplication object creation:

QCoreApplication::setAttribute(Qt::AA_UseSoftwareOpenGL);
QQuickWindow::setSceneGraphBackend(QSGRendererInterface::Software);

QGuiApplication app(argc, argv);

So all became ok as you can see on "Normal.png" picture.

I have added these lines of code to the standard Qt Gallery example and have compliled
this demo application for Windows. I have tried to switch UI between QuickControl
standard styles (Default, Material, Universal) as you can see on "Settings.png" picture.
The Default and Universal styles are looking good.
But when I am using the Material style the application graphics is looking very strange
as you can see on "Material.png" picture. Some controls are transparent.
The strange circles appeared etc.

So when I use the software OpenGL rendering I cannot normally use the Material style.
But when I use the default OpenGL rendering I have fuzzy user interface. But in this case
the Material style is looking normally.

The gallery Qt demo project source files just a little bit modified are here.