This is what I think may be happening. Go to Google and type in Partmaster then follow the prompts to your model number. Find dispenser and click on that part and a picture will show up with the dispenser shown upside down. That nozzle that you see is of course where the fill water rushes through via a rubbber hose to fill the machine. One half of that nozzle though acts as a breather and if that gets blocked up inside your machine, as it fills up, goes into a semi vacuum mode which causes the filling water to flood out of the soap box because the air within the machine, being displaced by the water, has nowhere to escape. The Partmaster part number is 3800498pm. Dismantle to check and clean it out before buying anything you do not need to!