This has happened to me twice now: I start a battle with a carrier in my force.

All of a sudden, I get the message that my carrier is "leaving the arena" and a countdown. Once the countdown reaches zero, the ship disappears and is designated as having "retreated." Turning or speeding up the carrier does not seem to make a difference. My carrier is NOT "leaving the arena." It's headed the same direction the whole rest of the fleet is headed: right at the enemy. What's going on? How do I stop this from happening.