Classic Theme on Win11 (23H2) - black explorer windows

There is a strange thing happening when using classic theme on Win11 (23H2).

When you open an explorer window, the window will be completely black for a second before everything is rendered as it should be.

I've experienced this behavior on two different computers, so it can't be coincidence or bad graphics card drivers or anything, it must be something that is different in Win11.

I just realized it has something to do with explorer patcher.

So I guess I should rather open a thread there.