I ended with a planet with a double Colony Capital.
I had sent a colony ship into a planet and got the usual confirm window. Confirmed it or so I thought because I got the window again.
See the yellow tile between them? Well, as building stuff seems a bit weird when dealing with those, I somehow ended being able to put a new factory there to be built.
Some turns later, I got the idle colony button that overides the Turn one. The factory in that yellow tile wouldn't complete and destroyign it wouldn't solve a very serious issue: the game is stuck on Idle Colony warning. cannot finish the turn.
Savegame file: Death By Idle Colony
Not really sure of how the double colony window happened but the interface sometimes is a bit...
Edit: whoops... more like this belong to Support maybe instead of feedback? *waves hand to move the thread*
Edit 2: Yay for more moving around! 