I'm not sure robster. I've got a couple of bushnell elites that are flat black no matter the lighting conditions, and I've got a couple that also turn sort of light brownish when the lighting gets dark... Not sure about looking directly into the sun, because I've never done it and it's quite overcast today.
Anyhow... I actually prefer those 2 scopes that look lighter under darkened conditions as when I am looking at black shadowed backgrounds hunting in the early morning or evening, I can clearly make out the reticle as opposed to the other 2.
Perhaps someone with more experience can illuminate lightbulb this matter better than myself.... But I do think I know what you mean.
-james