Strange offset when posisng armature

This is the first model I’ve ever rigged, and things were going smoothly up until this one point. I had rigged and weight painted the body, head, and character’s right arm, but realized I needed to subdivide the forearm’s bone several times to allow the arm to deform decently when the hand is twisted. After I repainted parts of the arm to introduce the new bones, the arm’s vertices appear to bend much more than the actual armature does when I pose it. The body and head still pose correctly, and when I try adding automatic weights to the opposite arm, it bends just fine too. It’s hard to describe the problem, but if you open up the .blend file and try to pose the character’s right arm, you’ll understand it pretty quickly. Even moving the body’s bones will show the problem.

Picture of the actual arm relative to the armature:

.blend file:
persondefault.blend (917 KB)

This is a common problem, there’s two armature modifiers on your arm mesh, one’s enough.

Ok, thanks, I was unsure because I really didn’t know which keywords to use to search for this kind of problem.