A fiber optic connector assembly and method for venting gas inside in a fiber optic connector sub-assembly. The fiber optic connector assembly includes a connector sub-assembly including a ferrule and a ferrule holder having a passage extending therethrough. A stiffener tube having a tube body disposed about a portion of at least one optical fiber supports insertion of the optical fiber into the ferrule holder passage. The stiffener tube contains at least one opening in its tube body configured to vent gas trapped inside the stiffener tube during assembly. In this manner, the trapped gas does not form a gas pocket in the bonding agent, which could compromise bonding among the optical fiber, stiffener tube, and connector sub-assembly.