Block Texture Bug

I loaded up a single player world, waited for the chunks to fully load and the blocks all looked a little strange. They had the textures of gates and trapdoors on the sides of them. The top looked fine. This never used to happen in 1.7.10 until now. Any idea what it could be?

Oh and before you lock the report, I would like to hear what the community have to say, just in case its on my end or their end also.

Thanks! 🙂