MMulcahy Have you tried spraying the seals to see if that will help them to flip correctly when slide is extended and retracted, this may also help with the sound you hear, the seals rubbing on the fiberglass as you are driving. The slide will move around a bit causing rubbing between the seals, if they are dry you will get a creaking noise. Something to try, a can of slide seal spray is cheap.Even though your rig is new, doesn't mean that the seals are lubed.
2014 Forester 3051s
2016 Nissan Pathfinder SL