Missing second crystal for me too, i wrote to support, the asap texted back that they are investigating, but we have a solution now: (creative use of game mechanism) Step by step reach the ledge, but do not jump to the portal. Just fell from high, you will break to very low hp, but stuck on a tree or rock or something. Use a potion to full hp, then you can jump and "climb" down to the cave. It worked for me first try. (The cave is straight under the watch tower)