“Pick all the numbers in the range with exactly the same probability” is a very important property of RNGs. Yes, skipping 16542 would be equally bad.

You can frame it around being “non predictable”, but then you need to define those words. It’s not, for example, a poker game where it’s trying to bluff you, right? It’s also not about just making predictions < 100% reliable and declaring victory. It must specifically make all predictions no better than random guessing, and that entails picking any number in range with equal probability, otherwise predictions like “it will be {hot spot}” or “it won’t be {cold spot}” do better than random chance. In this case, specifically, I can predict with 100% accuracy that the result won’t be 0, and that’s a flaw in its unpredictability. I can also predict a bunch of other things with slightly higher accuracy than random guessing, like that it will be odd or greater than max ÷ 2.