Background changes half way through game?

EDIT: title is wrong i was supposed to type GROUND changes color not background.

Hi, i exported to WebGL and Windows, on the WebGL version the ground randomly changes color after a few seconds playing the game to where everything is the same color and it's hard to see. In the Windows version it stays the same and works how it should. https://ancientshado.itch.io/shadocubeweb can anyone tell me how to fix this or why this is happening?