Possible faulty inlet solenoid valve rubber not seating allowing water into machine.(change valve)
try this though first,
Your machine may also back filling through the sink waste.
isolate the water to machine by turning off inline taps remove the water pipe/s hang in a bucket.fill the sink with water then drain down after half a dozen times if machine now starts to contain water it MUST BE COMING FROM SINK clean out the u bend pipe. Raise the height of the drain hose between the sink u bend and machine to prevent back siphoning .
wirecutterman
March 2009