from where I'm sitting ( on my couch if you are wondering) ,that shock you took a pic of looks blown.... You can see the "moist" looking dirt sticking to the bottom of the resevoir. I would get it looked at, or take it off the truck and try to cycle it. if its really easy to move, its blown. Take you 10 minutes to take it off the truck.
Oh and i know the shock doesnt hold the truck up, but it could be prematurely wearing the leaf on that side.
---------- Post added at 05:23 PM ---------- Previous post was at 05:15 PM ----------
Oh wait, your truck only has 8k miles on it... Did you happen to just tow something , or go offroading? The leaf springs might just breaking in. That's really common for one side to do that. But honestly, its probably just the Raptor lean. They all do it.