With only a small amount of testing I could only get this bug to occur where it first occurred. It didn't happen in any other save or in other spots in the original save.

I have attached screenshots with the environment that it crashes with. Additionally the world is a mostly empty superflat world with a layer of bedrock, 30 layers of dirt, and a layer of grass. The black and white pattern that is visible extends on the outside of a 16x16x16 cube, and there is a concept house I am working on in the inside of that cube.

One of the crash reports has also been attached. The main part appears to be near the top and says "java.lang.IllegalArgumentException: Cannot get property bcj

{name=variant, clazz=class azb, values=[stone, sandstone, wood_old, cobblestone, brick, stone_brick, nether_brick, quartz]}

as it does not exist!"