I saw this on the web. Never saw ivy peel off like this. I always heard it would stick like a SOB to brick and was hard to get off.
So I searched around to find the story, and a million Pintrest false leads later,
I found this picture from a guy who worked across the street. He said it had been rainy and the ivy just slumped off.
Apparently it's a thing that sometimes happens.

This one happened during a wind storm.