Unreported exception thrown!

Recreation:
Game crashed in creative mode, with debug screen, on bonemealing jungle wood saplings in superflat world and then jumping trough/over them onto grass and most likely (not sure) bonemealing grass.

I looked for a second into the code, it seems to be something with GUI, maybe the tree grew and block info has changed. I will try to do further testing.

P.S.- I am unable to recreate the crash.