The bug makes it so when you use fast graphics it makes leaves in your inventory / in your hand still be fancy and when placed down look really sketchy. Same with the 3D items, in fancy they are 3D and spin but with fast they are 3D but don't spin. It causes some framerate lag along with it. It might just be me using the Optifine mod to change my settings and it messes up the settings on vanilla. But I'm not sure. If it could be tested, it would be great.