Other behavior that is likely related includes stacks of items showing "0" or even negative numbers down to "-09" in the case of a stack of eggs being thrown with a held-down right click. Clicking on a stack of 0 golden apples, after having just fed two horses, caused it to disappear, but the game did not crash. Invalid numbers render as red instead of white.
I think this issue instantly killed a mule with 13 hearts health when I dismounted, dropping the saddle, leather, chest, and all contents of chest. Later it brought a horse with 15 hearts and diamond horse armor from full health to 2.5 hearts. Both times dismounted at a height of 1 or two blocks.