Iīm a little bit skeptical about this explanation.
First: the imageīs geometry donīt seems to be in agreement with your thesis of "vanishing of shadows". I think that it would occur if the source of the light were close to the lens (POV). But when you look to the shadows, you see that some objects display two shadows, inclined with respect one another, what probably means that there are two light sources in some distance of each side of the lens. I think this geometry isnīt very probable to cause any "vanishing of shadows" at the designated place of the image...
The "Vanishing of shadows" happens differently depending on the number of light sources. If you have only one light source on the optical axis of the lens, you effectively see no shadows at all in the picture. Photographers sometimes use ring flashes surrounding the lens to achieve this. If the sun is the light source, you will see shadows away from the centre of the picture due to the increasing "parallax" angle.
But in this picture there are at least two light sources, one on each side of the lens. On the left side of the picture you see the shadow cast by the left lamp, and on the right side the shadow cast by the right-side lamp. In the middle of the picture both lamps have equal brightness and so each lamp cancels out the shadow cast by the second lamp (unless the feature is big enough so that the lamps create two overlapping shadows). The result is a low contrast area.