Thanks for your reply,
Before I could try out your solution, I've realized there's a bigger problem going on - application of a preset causes a majority of the ground tiles not to show up in the sim, no matter how many times I cleared the cache, rebuilt the scenery library, etc. I've attached more screenshots showing this problem, and if you look closely to my original screenshots above, you can also notice blue spots along the ground.
After several hours of trying to solve the problem, I have had no other choice but to reinstall the entire simulator and all associated addons.
Out of curiosity, I did a fresh install of P3Dv4 and immediately installed RDShade 1.0.0 and applied the same preset, and the same problem appeared.
I am now on my second reinstall of the sim.