When we bought our 2017 Bounder Class A the Dealer the night before we picked up parked the RV opened the slides it was on a slight hill and did not have the jacks down. Due to be un-level the gears on one slide skipped a tooth causing the top of the slide to close all the way and the bottom since it was a tooth off left a gap at the bottom. The entire slide had to be removed and re-aligned.
NEVER open slides without Jacks down and level it is not about the frame or structure as it is more about damaging the gear alignment. It is not an easy fix...