When replacing lower intake manifold gaskets, it's recommended to retorque after a heat cycle or two. Are you guys removing the heater core coolant tube again to retorque that one bolt?
You're not retorquing for hardware backing off. You're retorquing because a couple of heat cycles between aluminum parts can compress a gasket and create vacuum leaks before heat-soak.
You're taking up the space made by all of the heat-soaked parts.