It's funny that this post came up because I have the same problem and I have had it for a couple of years now. Some times it drives me crazy, then other times it doesn't happen at all. I know it has to do with the humidity and all. I was just thinking that I believe mine is attached to the wooden floor joists with metal straps under the deck. This way you attach the plastic planking, but don't see any screws or nails. Maybe if I ground those mounting straps, I could dissipate the electric discharge.
