[Fingers]

If this occurs when you tell your flagship to turn in place, then it's normal behavior. The escort ships try to maintain their assigned spots in relation to the flagship, so if you turn right (without moving forward) any escort ships on the right side will have to turn around to go to their new spots (since the ships can only move forward). If the flagship is moving forward as it turns, the escort AI is able to drift backward in formation just by slowing down.