I've brought mine into the dealership for this same annoying issue. The dealer says the hood is fine and they couldn't replicate the problem. It's true that the fit seems tight but at about 45+ mph with a bit of a crosswind, the hood begins to shake and on a two lane road, if an oncoming semi passes, the hood actually shakes violently. Contacted Nissanhelp.com and was told there were no other complaints and that I should take it to another dealer to have them test and see if the problem could be replicated. Haven't had the chance to do that but took my iPad and set it up on the dash and have a recorded video of the issue. Intend to bring it back to my dealer to show them when time permits. May post on YouTube if I don't get this resolved.
This is the single biggest complaint about my purchase: Have a 2008 Altima and it's great. My fear is that this is a design flaw and the hood doesn't have enough structural integrity to keep it from fluttering. Infiniti hood design is different so it's probably just a Pathfinder problem.
And... where's the stainless steel rear bumper protector offered as an aftermarket accessory?