Using .50 or .51, connected textures controlled by Optifine are not working (glass, bookshelves, Conquest Reforged blocks, etc). I'm not sure of your support or stance on Optifine. Versions .46 and earlier do not break other connected textures, but I cannot downgrade because of world corruption. I will also mention this problem on Optifine's MC forum thread.

I don't know what optifine does, and I have no way to test this issue. If anyone from their side has a suggestion I'm open to it, but there's not much I can do now.

This is superceded by #273