This is a new game started with the release version of 1.6 with Mercenaries.
I have a custom version of the constructor which is much cheaper to build than the default beginning one and the same for the colony ship. I normally build the cheap constructor, move it back into the shipyard and upgrade it to the cheap colony ship, then launch the colony ship when it is ready.
This time, when I chose to upgrade the cheap constructor, I then chose Cancel to see what would happen. The game seemed to pause for about 2 seconds, then it crashed to the desktop.
Submitted Ticket ID #VVA-860-83119 with a saved game just before it happens.