I have a wm63 and encountered a similar problem when it was brand new. The only difference was mine did it only on quick wash, every other cycle was ok. I phoned hotpoint and I know this sounds weird but they told me to ensure the discharge hose looped higher than the inlets before discharging.
Yeh, totally opposite of what you'd think but it cures the dial sticking on quick wash.
S. Park
January 2005