You surely haven't go into an invisible object: the custom collision data for the scenery only has data for actual visible objects so, it's correct the scenery would block you against such objects and, in fact, it's a new feature that no other FSX scenery has.
You might have not noticed, maybe it was just the apron lamp pole, and if that space was too cramped for that airplane, possibly one of the wings was colliding with it, and it might not be so obvious at night.