Where did you measure at? Wheels are well known for mot running true, even the wheel flanges on the axles can have a little tweak to them.
Was the level zero'd? How about spin the level 180° to confirm the reading?
More than likely the axle housing has a little bend in it. Not horrible at this time, but keep an eye on it. The housings do flex as well. Jack the truck up by the pumpkin and watch the camber numbers change again. The axles are splined to so they don't bind when the housing flexes. Ever pull and old axle apart and notice the splines are worn down? It has flexed and walked a lot in it's life. Bent slightly will wear splines as well, they will rub as they act like a CV joint. Completely normal and expected to a degree. Circle track racers have been known to intentionally bend axle housings to make more favorable camber and toe settings (full floater with outer splines allows more angle). But they are also more willing to make things like axle shafts a consumable item expecting the wear.