What happens when OpenGL and GDI are mixed (Double Buffering)?

I made a application including OpenGL Double-Buffering Drawing
and GDI Double-Buffering Drawing.
One starts the app with OpenGL drawing.
L-Button click is a switch of OpenGL drawing mode and GDI drawing mode.
( .exe in attachment )
Win32Project2.zip (21.1 MB)

The application fails to switch from OpenGL to GDI on laptops:
Laptops with Quadro RTX Laptop and the latest driver (528.52 in my environment),
never fails with somewhat older versions of driver.
The internal change has caused a external change!
I found in Nvidia Control Panel that
the section “OpenGL GDI compatibility” affects:
succeeds in compatibility mode, fails in performance mode.
There is no such a difference in older driver, as well as desktop.

I am interested in what happened.

As you know, it is not allowed that
mixing OpenGL and GDI in a double-buffered window.
However, they are compatible on laptops with older driver and on desktops.

1 . What has changed?

2 . Why this occurs only in Laptops? Differences between Desktops and Laptops.