Anyone seen this?

Wondering why I have a 6 km egg from a 12 km I was hatching 🤷🏽‍♂️ I also looked up 6 km eggs and was surprised to see very little

Wondering why I have a 6 km egg from a 12 km I was hatching 🤷🏽‍♂️ I also looked up 6 km eggs and was surprised to see very little