Mushroom blocks deleted

Some special variants of the mushroom blocks seem to have just disappeared in the latest minecraft version.

This has largely broken a part of my adventure map and other peoples' creation(s) as well.

Variants affected (note, cannot be spawned in-game without world edit or mcedit): 99:11 , 99:12, 99:13, 100:11, 100:12, 100:13