Can't really tell, but looks like the outside rubber D seal may be in contact with the RV? It it's really only a half inch and the seal is slightly compressed, I would probably leave it alone.
BUT, it is new, so take it back and have them adjust the stops if necessary.
I have one slide that when retracted is tight at the top and a little over 1/2" at the bottom. Not enough for me to want to adjust it and haven't had any problems. Sometimes fixing things leads to other problems
Scott and Liz - Southern NM
2012 Wildcat Sterling 32RL - w/level up (best option ever)
2007 Chevy 2500HD 4dr short bed Duramax w/allison
Reese Fifth Airborne air ride king pin coupler with Sidewinder