The copper grates aren't working correctly
I tried to put mobs into copper grates because it said that it doesn't suffocate mobs.
Then the villager and the new bat died inside of it
Steps to Reproduce:
1.Put a piston and a grate above a mob
2.Power it.
3. The mob dies
Environment
Put your operating system (Windows 7, Windows XP, OSX) and Java version if you know it here
This is already tracked in MC-266056