there are 2 possibles
1) drainage hose is connected to the sink u bend, sink water running back into machine,
( cure ) raise the height of the pipe between the washer and the u bend to just under the work top if possible.
2) the cold fill inlet valve is letting past could be grit on the seating or a split/perished washer change the inlet solenoid valve in the machine
wirecutterman
March 2010