I’m only just returning to the game after uninstalling maybe a year ago now when I went to see my dragons again and found that my Telement is missing some stones that I’m pretty sure i should have unlocked.
Those evo stones were interchangeable. You could use them on each of the 3 Mythics that season. Do you have J’elithos or Durgotth at emerald tier? I did that and had to claim the other branch to get the missing stones.