only 1 of my 4 tires is worn off on the inside

Take a close look at the tire to make sure it is very round and flat across the tread. MAXXIS are good but not perfect. I have had tread separation.

Also check the springs have a nice arch to them. Mine were flat and sagging bad enough at one point to throw the alignment off.

If you find absolutely nothing you can swap the tire to another position or get a new tire. If it repeats you are probably looking at a new axle.