the top right lighting is a switch
I've noticed that the section that doesn't stretch on a dock is always sharper than the section between the stretch. Which I think is what you are pointing out I.R.? The vivid white on the upper right of the dock on the left side of the screen? It's something with how OD handles the graphics I think. It's more noticeable on some docks, especially those that have a light color on the edges.
Unless that's not what you meant. However, it is still an issue that perplexes me sometimes.