Aye the anatomy of that particular horse is a bit off right enough. To be honest, I don't think equine anatomy is Hara's strong point in general.
Lmfao, it's every horse in Kingdom, and this particular horse looks like the thing of nightmares, not only anatomy wise. Looks like a human horse hybrid, and that is Hara trying his best cause it's a chapter cover art
Aside from anatomy which Owl Ki already touched on, Hara is terrible at shading, he shades like I used to back in Grade 2 just a bunch of random thick lines everywhere. This is the mark of a weak artist, Isayama was notoriously bad here too, it's why their art looks amateur in a similar way, lacks the sense of speed during movement, and side profiles are especially bad cause they're not great at drawing dimensions. He has no idea of the concept of shadows, it's an eyesore.
Sometimes he cooks though cause he does have a lot of detail when it comes to foliage, landscapes, fabrics, and armour.