Found this today on an inspection. I wanted to know if any of you guys have seen this before? The plumbing vent stacks and flashing boots were melted above the roof shingles. They were located within 10 feet of the chimney. The chimney had a large horizontal separation crack inside the attic under the roof decking, but there were no signs of heat damage to the vent stacks inside the attic, only at the exterior. This was a pre-listing inspection for my client, and they are the original owner. There is no history or evidence of any chimney fires. It gets hot here in Atlanta during the summer months, but not hot enough to melt PVC. The roof has been replaced within the last 11 months. Any ideas? (See attached photos) Thanks for any feedback.