I've had this error too, and it's not related to system performance at all. For me, this bug happened mainly in the endgame phase, where I'd conqured all but 1 planet and was making Huge hull size ships every turn for score.
Sometimes when I clicked 'turn', the turn button would temporarily dissapear while ships moved -- I understand that's due to a large volume of ship movement. The bug occured when one of those ships sometimes reached their waypoints and would sit there, between turns, holding up the turn progress, waiting for orders. This is the game behavior I considered bug-worthy. Even when I hit 'tab' and selected the ship the game was telling me still had moves left, I couldn't give it move orders or skip its turn with the spacebar. The only way I could un-jam the stuck turn was to select another ship with moves left and give it movement orders. After I would move a random ship, the turn would unjam.
This isn't a performance issue. It's a "feature" designed to help keep the player from wasting starship movement. The problem is that the "feature" is also bugged, so instead of informing the player of remaining ship movement *DURING* the turn, it does it between turns, and then won't let you move the ship it directs you to.
