I think your pump or more accurately magnet may be defective. Maybe it was coated too think or some other error. OR they have already had more then one production run. I just tried my pump on 1/2" - only my front pane is 1/2 and it seemed to hold fine. I pulled on the cord and the pump without issue. My phone is only at 5% so I'll try again later and turn it on and take a quick video clip.