Does anyone else have a 2014 Altima that occasionally rattles underneath after going over a bump?

Nothing should be loose on a 2014 anything, and even if it is, the dealer should not dismiss it such a cavalier manner. I would take it back, and ask to spell with the GM or the owner. I this shit I went out 40 years ago. Don't take no for an answer. If you don't get anywhere with my first suggestions, do a tell all all on Yelp and deliver them a copy when it appears. That should do the trick. If not I have many more tricks. Hope this helps.

I had a rattle on my 2015 that was coming from the trunk area. At top of the trunk cargo area, there are two long rods that assist in trunk opening and are held together by a plastic holder. Sometimes, one of the rods (or both) slip out of this holder and start banging together. To fix, simply insert the rod(s) back into the plastic holder and the rattle goes away.