I wonder if people with slide issues are operating them wrong? I learned from my dealer when I bought my pop-up to open the entire camper up first, before leveling. It's even more crucial on the pop-up because there are so many moving parts that are tied into the frame. Plus the frame was a lot less heavy duty because it's only carrying 3500 lbs vs 9K potentially.
I have followed this same method on my TT and have had zero issues. Makes a lot of sense. If you level the camper first, you may have the frame out of alignment. There has to be a lot less stress on moving components under a "natural state" vs having one side jacked up and possibly tweaking the frame and then deploying.
I know some manf. say to level and then deploy but that just doesn't make sense to me at all. Too easy to rip stuff up imo.
What I have done is gone to a flat parking lot and got the camper leveled while open. Then I close it all up and put the level bubble as being leveled. Obviously it's not level when closed as the slide tilts the coach a little. But, then it will be leveled when open.