one thing i have noticed while using the akkan is that when i order it to move to a different gravity well the fleet doesnt come with it.  I can only assume that somehow the code for telling the ship to go to a non friendly/unclaimed planet is that the ship is receiving the colonize command rather then just "move to that gravity well".

As a result the escort fleet isnt movnig with the Akkan, much to my suprise when doing other things", i havent tested it out with the other  colony captial ships so that would need other's to check on that.