macOS layer-backed OpenGL windows retina -> non-retina move bug

The bug reproduces with a retina MacBook with a connected non-retina screen, that is used as a separate screen, not mirroring the main screen on it.

1. Create window containing an QOpenGLWidget, like "hellogl2" example from Qt source.
2. Build and launch it regularly – works as expected.
3. Launch it with command line "QT_MAC_WANTS_LAYER=1 ./hellogl2.app/Contents/MacOS/hellogl2"
4. It works fine on the main (retina) screen.
5. Drag it to the secondary (non retina) screen and the rendering is "zoomed-out", all the content is displayed only in left-lower quarter of the window, the rest is black.

If the layer-backed window with QOpenGLWidget inside is created on the non-retina screen and then moved to retina screen the effect is opposite – all the window content is "zoomed-in", so that the whole window displays only one quarter of its actual content.

Screenshots attached.