This problem is due to a poor drainage system that is typical of this model, mine has been doing it for years, (began after it was about 3 years old,) and has now failed completely because of an unrelated door closing issue. I had it serviced for the draining fault once but it came back within 2 months.
Only workaround is to keep turning it to (E)-drain or tip the water out the front, I'm off to buy another now and it wont be a Whirlpool......Good luck with yours.
Chilli
January 2005