Beaconator Achievement won't unlock.

What I expected to happen was:

When I constructed a full beacon in survival mode, I thought I would get the achievement.

What actually happened was:

Instead, it never gave me the achievement.

Steps to Reproduce:
1. Spawn and kill the Wither in survival mode.
2. Craft a beacon.
3. Build a full beacon pyramid. You can tell it's the full version if all of the beacon effects are available.
4. This is a very hard bug to reproduce considering you'll need to kill the Wither AND get 164 iron, gold, emerald, or diamond blocks.