Mobs jump franticly when lit on fire

So. This bug is fantasticly fun to watch.

It definitely did not happen in 15w51b, I just updated and the jumping! Whew, the jumping.

Light a mob on fire (creeper, zombie, sheep all tested) either with a flame bow or, in the case of zombies, with daylight, and they hop around crazy until the fire is put out.

Its amazingly funny.

But almost certainly not intended, lol