Working in Texas I see a lot of roofing jacks, and flashing fasteners where the nails begin to oxidize because the loose their galvanized protective layer, or they have been caulked and the caulk shrinks and cracks. these nails squeeze out of the decking like a water melon seed between your fingers. I list these as roofing deficiencies that require maintenance to correct. I recommend installing new nails and caulking over the old location. This simple maintenance prevents blow offs and extend the life of the roofing components integrity.