Edit: It was the regional difficulty. Once I set difficulty to hard, it worked nearly straight away.

I am trying to get the 'Diamonds to you!' achievement in single player in 1.11.2. I'd rather not have to connect another client on the LAN so, I am trying to throw a diamond at a zombie and get them to pick it up for the achievement. I think I have done this in previous games and, it seems like from reading/watching videos, this should work on 55% of zombies on normal difficulty. I have tried throwing it at and infront of hundreds of zombies, mostly from a zombie spawner but, none of them pick up the diamond. Has something changed or, is there a bug? Has anyone done this in 1.11.2 and, if so, how many attempts did it take? Did you throw it at or infront of zombies? Can anyone think of what might be wrong?

Edit: Creepers do destroy blocks so, it sounds like it is not the mobGriefing rule thing. I checked using /gamerule mobGriefing and, it is true.

Edit: looks like I was wrong about it being 55%, it is 0-55% based on regional difficulty so, could be 0 in all the chunks I have tried in (I don't know what the relationship is). I will try on hard where it is always above 6.something%.

Edit: It was the regional difficulty. Once I set difficulty to hard, it worked nearly straight away.