Instant crash when I press a lever to a sticky piston + slime block

Hello,

I found a critical bug, I don't know if it only happen in beta but when You try to press a lever to activate a sticky piston pushing a slime block joined to observer the game hard freeze and we can't do more than Alt+F4...texte souligné

I don't know if I explained it good but I send you a screenshot to show you the set up I used

Hope for any answers, thanks !

EDIT: I tried different set up and it looks like it's only with Sticky piston + Slime block that the game crash, the observer is not the problem

EDIT 2: The slime Block is not the problem too, its only when you try to activate a sticky piston pushing any block with a lever that the game crash