Superflat Customize Menu Crash

IMPORTANT: This was Discovered after I Found the Torch Bottom of Block Placement Crash Bug. So i do not know if it was caused by the subsequent crash or not but it still persists after restarting the game several time.

When i Go to Create a new world and change it first to Superflat world; It crashed when i click on the Customize menu.

17w15a > Singleplayer > Create New World > More World Options... > World Type: Superflat > Customize