Echo that, I'd go over your box with a fine toothed comb, and maybe make a call to Pelican.

And if you are going to use a Nalgene for long term, get a new lid if you've been using this one for a while. Then fill the bottle with BOILING water, and seal immediately, as tight as you can (use a glove to handle the bottle)- as the water cools, the resulting vacuum will "can" the bottle.

Those two, and the possibility of putting something in wet, are the three culprits that spring to mind.