Hey @tygerin
Welcome to our community and apologies for the frustrating issue.
Please make sure to build the temple in a place that has nothing around it that would block it, be it walls, placeables or elements of the terrain. People usually build it on top of foundations at a certain height to avoid possible issues.
Our team is aware that sometimes altars can present issues when upgrading them and they’re looking into it.
Thanks for your feedback.