The damage is bent inward from outside the coach and into the interior. That means something on the steps is hitting the frame and then pushing inwards when closing.
All you have to do is step inside the coach and have somebody else lift the steps up while you watch to see what is hitting and bending it. then make sure in the future you don't do whatever it was that you were doing to cause the impact.
the other possibility is after the steps are up and locked the closing door hits the steps and pushes them further into the coach and bends the frame. But if that was the case, I would think there would be marks on the inside of the door where it contacts the steps.
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2001 Suburban 4x4. 6.0L, 4.10 3/4 ton **** 2005 Jayco Jay Flight 27BH **** 1986 Coleman Columbia Popup