probable memory leak when resizing QOpenGLWidget

When I resize a window with QOpenGLWidget in it with a mouse it tends to accumulate memory which is never freed, not even after a long time. It happens however only on some machines. After about 30 seconds of dragging left bottom corner of the window, the process occupies more than 1 GB of RAM. See the attached GIF.

This is the code I was testing.

#include <QApplication>
#include <QOpenGLWindow>

int main(int argc, char *argv[])
{
    QApplication a(argc, argv);
    QOpenGLWindow w;
    w.show();
    return a.exec();
}

About machine: Windows 10 64-bit, 16 GB RAM, Intel(R) Core(TM) i7-6700 CPU, AMD Radeon R5 430, 4K display Dell.

I tried the same on other machine and this problem did not occur.