I'd say more poor pose than anatomy. There's like some kind of lack of depth perception, making her upper body look huge and further to the side than it should be. Otherwise, this is really well drawn.
It's more the angle of the leg than the size, but they're right, it is a bit small, considering that the foreshortening/proximity to the viewer would make it larger.
That said, though, it isn't bad enough to be flagged/deleted. Tag it as an error and move on.
