There is a bug, many people in my company have experienced while creating a terrain. Essentially, sometimes when you're in the process of trying to create a terrain from a point cloud, the dgn says that no point cloud is attached. Previously, I could just close and open the dgn and it would fix itself, but seemingly in ProjectWise this doesn't work, and you have to create a brand-new file and attached the point cloud to get it recognized by the create terrain tool.