I have just been in Gehn to search for my soccer ball. I found all the mounds except for the kivas to be missing/invisible. When I run away from the linkin point in any direction my avatar rises and falls fairly often. I assume this is when I run over an invisible mound. I am also unable to find the soccer ball. I do not know if it is also missing/invisible. Everything else seems to be there. I completed the age a few years ago.
Regards
Philip