The lens is oversampling the sensor.
I'm afraid I don't understand this statement. A lens is an analog device; I don't see how it can "sample" anything.
Ideally, it provides a perfect image focused upon the sensor - that's the goal, is it not? At worst, the image has lost some resolution, and perhaps has some aberrations introduced. But moire isn't either of these two effects. As the respondent below pointed out, you never see this sort of thing with film (an analog media).
So I would assume it is a byproduct of the way the system samples the sensor array and merges the four color pixels into one. But the lens has nothing to do with that, unless you are suggesting that there is something inherent to the performance of the lens that causes this effect when the sensor samples.
Would you please explain this (or point me to a reference that does)?