Boards that have propensity to cup usually do so for a variety of reasons, none of which have to do with the fastening systems. The main reason boards cup is from moisture. Ventilation of the deck is a key factor. If the deck is low to the ground and the ground does not drain fast enough, the evaporating moisture rises and is trapped underneath the deck.

Then the bottom of the boards, especially hardwoods, dries much more slowly than the top of the board which has free air flow and sunlight.

The best prevention is to allow ventilation or, if possible, to spread a healthy layer of coarse gravel or other material which allows the rain water to soak through and then dry.

Cupping is unattractive but a popular remedy is to belt sand the cupped edges.