12 week old sealed deck water stains

12 weeks ago our contractor installed a 750 foot heartwood redwood deck to our home. He sealed it by aplying one coat of TWP500 (clear). It rained one month later, and water stained the deck. The deck also looks very dry now, and water does not bead on it. After the coat of TWP500 had been applied, the deck felt "slippery", and a light gold color would rub off on shoes, pants, etc. We applied a second coat to an area of the railing 5 days ago, and it looked good, but we had a massive rain storm last night and now the second coat area is spotty and light in color. Is there something we did wrong? Should we have used a different product? We want the beauty of the redwood to show, that is why we chose a clear sealer.