I would guess that maybe it is from the epidermis becoming a little loose during tanning. I've seen this before on an "iffy" cape I had a couple of years ago. You don't want to re-hydrate the leather, because if that is what is causing the hair to lift it could fall out. I would use a warm/hot damp cloth and just dampen the hair itself, then put a liberal amount of hair gel on it and try to "re-train" the hair back to normal. You may have to apply the gel a couple of times to get all of the hair to lay down, but this should work. It is NOT however, from the hair being longer!!!!!!!