That isn't Jamba, that is WOW. You can't take a escort quest on your alts, or they don't get credit. You just get it on your main. Just watch for the word escort, that is the key. Or if you remember more, an event works the same way (fight waves of mobs, etc). Not much you can do about it, other than remember which ones to not accept on your alts, just your main. With Jamba/Multiboxer/macro, you can just get on your main and then accept it on your alts.