It’s not really a bug but part of the system. Whenever you’re on a roof you usually slide off but if you land in a certain spot with almost no momentum you can balance/get stuck there but if you don’t move for 4 seconds the system automatically bounces you up. These spots aren’t limited to doomfist but he can access them the easiest. Some heroes like pharah, ashe and echo can get in some of these spots and I imagine multiple people could if they had a mei, sym and lucio