Random artifacts with cube demo

[rageshkrishna]

Hi everyone! I'm trying out the 480 x 320 Demo 3d Cube on a no-name ILI9486 (I think) display with an 8-bit parallel interface. The cube is visible and animates well, but I keep getting random pixels around the screen like this:

They keep changing as the cube moves around the screen.

I see no issues with just text demos, so I am almost certain that my user_setup is correct. I also see this happening with the sprite cube demo, where occasionally a part of the cube will be frozen on one part of the screen and eventually gets blanked out when the animated cube moves over it again.

Any ideas on what could cause this? Is it the display itself, or something else?