I have sent a saved game at turn 371 to Scott and Jesse at SD to check out but it had the same reported problem. I did have ships on auto-explore, I'll try turning that off tonight and see it the game can progress, if so then this is a minor bug with workaround but still annoying as the auto-explore is a very neato kind of feature in my book. If not, then this is a game-ender bug - do not pas go do not collect $200 - GAME OVER kind of bug.
Here's to looking forward to a fix...