Stains on attic nails

Do you call out small stains on attic sheathing nail penetrations?

I look for the reason why the nails are causing the stains then call that out .
Example Bath fan exhaust into attic Raises moisture in attic,needs to be vented to out side .

6 year old house , ridge and soffit vents look ok, pretty hot in attic.

Sounds to me like Moist air is getting into attic from the home . Does the bath go out side Is the attic dooor Insulated and gasketed . how about other holes from home to attic . You need to find out where the air is getting into attic .

No, I got to see drip marks in the insulation first.

Hot in the attic in New Hamshire in May? What was the outdoor temp? Are vents blocked but only “look” OK?

I spent an hour in an attic in PA
was hot today

I worked with roofers that used rusted nails.
IE: always used open box pickup trucks, or 5 tom trucks. It would rain on the product, felt, shingles, etc. Nails got week. Stored in a damp environment. they will rust.
Mr.Cooke makes sense. Find the deficiency in the attic.

Seeing you are from NH I thought of ICE STORMS? Mixed with a power outage and the homes temperature dropped to create a dew point in the attic. Frost built on the underside of the decking.
Is the home in a rural setting. In a lower valley.
Only a shot in the dark, Steve but your detective skills must be turned on when you see that.
Could have been an isolated occurrence.
Even more reason to look for the deficiency in the attic.
Did you follow all the vents from all the appliances out side and account for every one. Bathroom vent, or any other source.
Damaged stack vent can cause moisture in an cold attic under the right conditions.
Calculate a dew pint link bellow. Good luck.