Roof Question - Thawed Near the Plumbing Vent

Hi all.

I have a client who is asking why their roof is frost covered throughout except for one plumbing vent. The area of the shingles around the vent pipe, she tells me, is thawed. Does this seem like an issue? This seems normal to me considering this is a roof penetration and some heat may transfer through the pipe. Any thoughts?



Warm moist air coming out of the plumbing vent condenses on the roof , Happens here too in cold weather .

Attic bypass at the plumbing vent

Wrong. That is the cause of ice buildup.