1.) In case a design is so sensitive the miniscule influence of the moon (capacitance, inductance, luminosity, gravity, shielding from cosmic rays etc) leads to a change of results, it is reasonable to assume the moon might have an influence.
But this means a design mistake has been made in the first place. The influence of a person with an electric wristwatch will be way bigger probably. It means the electronics design is unreliable in the first place.
2.) It is darker in moonless nights, so with optical sensors feedback will be different. (or other types of sensors, for that matter)
3.) If your electronics are right on the waterfront of tidal waters, because tides are of a different height depending on the phase of moon, the effects of saltwater on the electronics might differ.
4.) Since there seems to be an influence of moon phase on people (even if only they believe there is), the interpretation of electronics results might be psychologically attributed to the moon (poor thing). Or maybe the users just use the stuff wrong.