It looks like evidence of a leak. Be aware that because water runs downhill, it is often difficult to determine the source of a leak. For example if the leak is on the high roof, the water could run down inside the wall, then across a framing member to it's lowest point and then drip on the ceiling a full story and several feet away from the location where water is entering the building.
Because the typical roof warranty is more limited than one might expect, the quality of any repair is often more directly related to the emphasis a roofing company places upon it's reputation than what is written on paper [This is why commercial projects often require a bond covering the installation of a new roof system].
My recommendation is to investigate for the source of the water and where it flowed by entering the attic space. Seeing where it is wet will often be far more informative than looking at the outside of the roof. Also, it is possible for water to enter a building during an unusual wind conditions.