I've been tracking this bug for the past few months. In pre-engine update (Original DX9 PSO2) you would only see this error in the character preview window and you zoomed in right on the face. Now with the NGS Engine Update, its everywhere and you'll see it during cinematics and in game. With far higher pixel densities 1440p and higher should have an easier time seeing it than 1080p and below.
I suspect this may be an issue with the Skeletal Animation System, but I'm not 100% sure on that.
Video with Examples: https://www.youtube.com/watch?v=aX8yU_kZctw
This is one of those bugs, when its pointed out you won't be able to unsee it in the future.