Anime models are kind of notorious for drawing impossible clothes if you don't guard against it in prompts and keep an eye out for them.

To the point where I noticed that navel and impossible crotch folds before I noticed that extra arm.

Realistic ones don't tend to have that issue must be the training data, worst of all "impossible clothes" is not tagged reliably. Are those models able to draw proper clavicles? Absolutely. But they'll also glue the collar to the skin because that's how artists like to draw stuff like latex.