I am finishing a game on .017 before I update to the final 1.1 release, so this point might be moot, but every colony I capture in this .017 game has a starport on a tile that cannot be built on, even with terraforming.

Generally, I prefer not to have loads of starports. I only build them on PQ12 or higher planets, or 10+ if I need more. It is sort-of convenient, however, to have a functioning startport on every planet that does not occupy a tile that could be used by something else, so my real question is, I guess, why can't I built them on useless tiles?