They're not adjustable ball joints, they're offset. Very few reasons they would ever be needed short of a bent axle or some fabrication issue with the axle/knuckles.
You don't have that many miles on the last BJ replacement if I recall. But if you can actually see neg camber on a 4wd, ball joints are pretty bad, OR outside shot, the wheel unit bearings could be bad, but they'd be trashed and un driveable, grinding, etc.
Do you have the print out from the last alignment? Did it show any camber issues.
You may have gotten cheap ball jts the last time and they're junked out.
Easy at home ball joint check. Jack up a front wheel slightly off the ground. With a pry bar, bar the wheel back and forth. If you feel more than like 1/8"? or so of movement or if you can noticeably see the camber angle of the wheel change, then they're bad. You can expect a little up and down movement but in and out movement is no Bueno.
Or take the tire off. Do the same thing where you can actually see the ball jts. Again, lateral play is no good, up and down is ok/subjective.