Hi, I have a fisher and paykel double dish drawer in my home that has developed a weird draining problem. about every other use one of the dish drawers will not drain completely, usually a 1/4" or so of dirty water remains in the washer. I've checked the drain screens of both the top and bottom and they are both clear of debris. I have not yet snaked the drain lines because I figure that if it fully drains about 50% of the time that there must be some other problem. Is this common with these washers? Thanks!