The shading of objects is always consistent across the entire overworld. North and south are bright, east and west are dark, up is the brightest and down is the darkest. Even the arm model and held items seen in first person view used to respect the lighting of the environment depending on the direction the player is facing, but as of snapshot 24w05a this is no longer the case.

Watch the attached videos for a comparison. The arm and items are clearly shaded, but they remain the exact same even after some crazy movement.