Now you mention it...

I've seen the same thing with a force composed of the VR Titan and two capitols trying to jump outsystem from a star... Of course, once noticed, you can easily rectify it by ordering the formation to move a little further from the gravity well boundary then reissuing the jump order, but that really isn't the point. If you're trying to hurriedly reinforce a friendly world (like I was) and get sidetracked, your rescue fleet just sits there, uselessly waiting. Maybe the titans need to be shuntable (you've probably seen the capships nudge blockading frigates and even other capitols aside to get to their objective) so when they are in the way, your ships push them aside to line up to jump.