The plastic decking is made from quite a variety of different plastics, depending on the brand. That's why I suggested it might be a brand-specific problem.
I can't speak to other brands, but I do know that Trex plants have plenty of static issues- from lint everywhere to frequent fires. I don't think you can assume any wood content helps. The plastic they use is quite the static factory.
Azek, by comparison, is a completely different plastic. I wonder how the static issue is with them.
