I live in Anchorage, AK and am having the exact same issue with my 2011 Prius sunroof. Took it to the dealership on Saturday to have them look at it, they said it was cosmetic. The dealership is calling toyota tomorrow to see if they will cover it; however, I am not hopeful. Our local dealership said the whole glass had to be replaced and the cost would be $2200 which seems ridiculous to me. One additional gripe, when they 'looked' at the problem, they made it even worse by lifting up the rubber in several spots. I will call and complain to the manager today. Please keep us posted on what toyota has to say. I intend on calling them myself if the local dealership isn't successful.
My 2011 Prius had deteriorating Moulding at the base of the moon roof pivot glass, where it meets the windshield. Photos below of the job. New moulding piece had glue points on either side that needed to be cut off to replace the old strip. Must also cut the same area of the old stripping to allow it to easily lift out. 6 total torx screws hold the pivoting glass and it is easily removed to make room for this job.