I have a one year old 2220 rolled edge with the same issue. Water will not drain out completely and leaves at least a 12" or more circle of water at each corner, sometimes more depending on the angle at which it hangs in the slings. It looks like the drain openings are not low enough to allow all water to exit. My deck in the areas around these corner drains is turning yellow and black from mold etc. The depressed area below each drain stays constantly filled with sand, dirt etc as it cannot get out. Did you ever get any info as to a solution???