This happens every once in a while, when I tell a constructor to autopilot to a starbase over several turns (not using rally points and not talking about one turn trips.) The constructor will arrive at the starbase, the starbase build dialog will pop up, I'll select the component, but the component won't be built. Instead, the constructor moves on top of the starbase and just sits there. All I have to do to make it work right is move the ship off the starbase and back on. The dialog then pops up again and the component builds as normal.
-Dewar
