Some assets are pink when loading a game using LoadUnityWeb

I wrote a small preloader that loads the actual game using WWW.LoadUnityWeb, and it looks like there’s a bug when trying to load certain games - some of the in game assets just turn into solid pink. Oddly enough, this only happens for the Windows web player, and works fine on MacOS. Here is an example (the problem only presents itself in-game, the menus are fine).

I couldn’t find any mention of this problem anywhere, anybody has any idea why this might happen?

I would say it is a matter of those shaders not being supported, or not being working correctly, in that platform.