Sorry if this isn't a bug but rather an issue on my end, I honestly have no clue. I installed Minecraft version 1.12 Pre-Release 1 and created a new world. I started doing what is standard and punched down a tree. After I did that, I put the logs in my crafting window and shift clicked the output to turn them all in to planks, causing my game to crash. I relaunched the game and attempted to craft again without shift clicking the output and crashed again. I will attach both crash reports for viewing and/or possible assistance.