Sounds like a similar problem we had with the '08 Rockwood 2605 we used to have. You need to adjust the stop bracket so the slide doesn't pull in too far at the bottom. I recall that I had to elongate the slot to adjust it were I wanted. To verify if that's what is needed, retract the slide until it stops then bump the 'out' button a little bit and see if that changes the gap you have at the top of the slide.
Nights camped in 2013 - 55, 2014 - 105, 2015 - 63