When locked the upper drawer can be pulled almost half inch exposing the documents stored in the first hanging folder. I would blame the lock which is located in the left side of the bottom drawer. If you pull the top drawer when the lock is on it twist most of the outfit. I would blame the quality and/or the gauge of the metal and the lack of internal reinforcement.
Unit is cheaply made for the price. Lock can easily be broken by just pulling hard on the drawers. I returned and purchased another filing cabinet from another store that was significantly higher quality. Best quality of the product was how smooth the drawers glided compared to most filing cabinets.