Crash due to redstone update

While a repeater is facing a piece of wool that has a redstone wire on top (to make it go upwards) and the repeater gets powered, the game crashes.
Upon reloading the world, the repeater is still on (and the wire too) even if the imput is off. Upon updating the repeater, the game crashes again.
When opening the world again, the repeater is off.

I am using Magic launcher 1.0.0 but no mods are loaded.