Achievements are taking too long to be earn. In general, it takes half an hour to earn. When you leave the game, you never win the achievement again, having to redo it
This bug was also in the early versions of 1.16.x.

Steps to Reproduce:
1. Try to make any achievement

Observed Results:
The achievement takes a very long time to arrive and if you leave your world, it will never come.

Expected Results:
The achievement should be earned immediatly.

Fixed in lastest version