Beacon achievements not awarded

I have a 1.16 snapshot world in survival (hardcore). I created a beacon, and laid it on a 4-level pyramid of iron blocks. I can get Haste II and speed-mine stone.

However, I was not awarded Bring Home the Beacon or Beaconator.

This is RC1 but I had the same issue in the pre-release from June 12th.

The world was created on 5/23/20 on the latest snapshot at the time.

I tried creating a new world in RC1 and this was not reproducible; I got both achievements.