So, I was messing around in creative, and I thought “hey, let's mess around with thera blocks”, so, I was placing down Thera grass, and the first thing I noticed was that the side of the block wasn't rendering right, with a grey side instead of the dirt side, which didn't seem right to me since the block in my inventory had the grass side rendering right, but when I placed it down it wasn't, so I just thought it would be good to bring this to your attention.

Caused by Optifine, keeping this open though as it's odd this only happens with Thera Grass.