Hello! We are saddened to hear of this experience! The Roomba 675 is designed to navigate using input from the camera, the Floor Tracking Sensor and from the Dirt Detect sensors. This would have the Roomba go over spots multiple times if higher levels of dirt or debris were detected. However the Roomba would still navigate around the room to ensure the entire room was covered. We would like to look into this experience with you. As we want to make sure that you get the best cleaning performance from your Roomba. So that we can assist, please reach out to our Technical Support team directly at 1-877-855-8593. We look forward to speaking with you! Sincerely, iRobot Customer Care