First let me say that your descriptive skills are top-notch. I understand exactly what you referred to.

Look at the bottom left of the image. There is one camel by himself. Then one level up there is a row of camels. The fourth camel "shadow" from the left has a white area superimposed on top of the dark "shadow". If the large dark shapes are supposed to be shadows then the white areas, which are supposed to be the actual camels, should also be in shadow.

The shadows of the two camels tell the entire tale here. Examine the shadows of the two camels you singled out and all becomes clear. The sunwardmost camel's shadow covers up the other camel-shadow's ankles only. Above that, the camel is hit by the sun and casts a shadow.

Also, the white shapes seem to have two shadows. Small dark shapes right adjacent to the white shapes of similar size to the white shapes, and then the large dark shapes that are obvious.
Short of Tatooine why should figures in a naturally lit scene have two shadows.

The second, small shadow is the dark side of the camel itself. It is not a shadow projected on the ground.