Affects Version/s: Minecraft 14w21a
Fix Version/s: None
Environment:Windows 7 64 bit
AMD Radeon HD 7850
Placing an item frame on any block will instantly crash the world.
Also, any already placed item frames from a 14w20b or previous world will instantly despawn when loading up the world in 14w21a.
Any items on those frames will be lost.
Create a new creative super flat world.
Place any solid blocks down.
Attempt to place an item frame on the block.