This is a new one for me… looks to be a defect of some kind, but I haven’t seen it before. Maybe caused during storage?
What do you guys think?
O ya, 20-year 3 tab in relatively good shape otherwise. There was only one small section (under a tree) affected and then two other small areas in valleys. Condition was present on probably around 5% of the roof surface. Soffit vents present, but blocked by insulation… gable vents, and ridge vents present.
Thanks in advance for any ideas.