If there is a tall item directly in front of the detergent tab tray, the water flow to the tray may be blocked preventing complete dissolving. Try rearranging the items in the top tray so the tray isn't blocked.
If there is a tall item directly in front of the detergent tab tray, the water flow to the tray may be blocked preventing complete dissolving. Try rearranging the items in the top tray so the tray isn't blocked.