Texture of 'Snow Grass Side' is different from 'Normal Grass Side'.

I was trying to find out if snow stacked when it was snowing, but discovered a very interesting problem. (I'm not sure if it's accidental or meant to be that way) Looking carefully, the texture of a normal grass block (side) is different to the snow grass block (side). Pictures attached below. I'm not talking about the color at the top changing to snow, look at the pixels very closely at the actual dirt part.