When fancy leaves is off "snow leaves" (ie the white leaves in snow biomes) will turn a solid black colour

I generated a world with fancy leaves on. I spawned in a snow biome and i noticed that the leaves where black. I switched on fancy leaves and i hit a block near them and they became normal. When i switched it back off they became black when i hit another block near them they turned black again.

Video is laggy because my screen rec settings messed up