Treated Lumber Concerns

The short version is you should always install a barrier between any metal from direct contact with ACQ treated wood unless the metal has been treated properly. Use approved wood screws for your application.

Typical galvanization processes do not guarantee ACQ will not deteriorate the steel over time.

So to be safe, use either non treated bearing type plywood base or self adhesive membrane type product.

The long version is in the link here.