Factories taking "extra" product components

Hi all- is any one else experiencing the issue where you drag an item for production, and you miss the little box, so it doesn't start? Only, it touched the box, so it "eats" the products required. So basically I spent component products but didn't get an item out of it. If it touches the production slot long enough to trigger taking warehouse items, it should grab the item and lock it in the slot area.