The scion temple isn't built on a wild improvement and both the ogre camp and scion temple are directly adjacent to the central city tile. Don't think they could be any closer to a city.
Any update on this? I'm having the same problem with this. It doesn't stop with sions either. I built an ogre camp and can't train ogres either. (Darklings train fine however, and have as long as I've been playing) Sorry, I spent over an hour searching for a post on this before posting this, https://forums.stardock.com/395809, but apparently you have to use the search engine at elementalgame.com , not the elemental forum on