You are the first person to ever notice that "missing" hose. Just kidding, everyone asks the same question. It is designed like that and your truck is fine.
What hose is missing? Under the hood of our 2012 RTL, at the top of the firewall, there is a black square solenoid(?) that is attached to cruise control with a open barb that seems to have been attached to a hose. Anyone know where it should connect to? :|