i recently did a reinstall of the entire FSX and these graphic anomalys did not appear untill i installed the KLAS addon as you can see from the images im getting strange rainbow colors on the runways and in the scenery. these photos are taken from the NGX with runway lights on
They don't have anything to do with KLAS, you are using the NGX, which uses its own custom runway lights, that are nothing special, just a plain semi-transparent texture projected on a large polygon that covers the ground around the airplane to create the effect.
Since FSX textures are DXT compressed, they have limited color depth and, when they are blended together in such complex way (the photoreal background blends its own night textures and FSX blends the PMDG custom light texture on top of it) the limited bit depth to create the blending will cause such color banding.
Of course, you wouldn't notice it so much on a default airport, that doesn't have an hi-res photoreal background and you will not notice too if you use a default airplane, even on KLAS, which doesn't use that trick to create custom runway lights.
