Secret Achievement No. 21?

When I go to the Beyond and scroll to the secret achievements, there is a 21st one after the Middle Ages one. However, when I am in a different simulation, there are only 20 secret achievements. Only Rank 8 in the beyond by the way. Also, I've unlocked both Uranus and Neptune, and I bought the Voyager 2 upgrade in the Augmentations Console, but I can't buy the upgrade to boost my Ice Planets.