Broken pixels at the top of video framebuffer in XQEMU

The top of video framebuffer is rewritten with "random" pixels. I looked it up closely in the hex editor, it seems like this part of memory is occupied with some code, exactly 3072 bytes in 24bpp space (1024 pixels), and this looks like memory corruption.

Nothing noticeable in the debug log, except known USB spam (reported in CORE-16352).

This didn't happen in the old ReactOS 0.2.5-xbox build, so marking this as regression.

Attached showcase screenshot and raw framebuffer dump of top pixels in 24 bits per pixel color space.