That's the way mine is. Barely visible so its not a big deal. No paint rubbing off either. I honestly don't think it'll happen unless someone is careless. Anytime i've adjusted the arms I pull them away from the armor.
That's not true at all. I knew about the paint flaking issue before I received my Thor and was extremely delicate with moving the arms. The left arm still had paint flake off. The right arm, which I use to hold the hammer, was rotated and moved up and down WAY more often and did not have a flaking issue at all.
It's a factory QC problem, because I received my replacement and do not have problems with flaking paint at all.
If the paint flaking issue was because of normal wear from movement, you would see the problem happening to BOTH arms, but many people are only having the issue with one arm on their figure.