Yeah I also have the same prob on a few of my VL3N's too.. I ALWAYS put paper around the connector just incase to catch drops. They do come good again though if you clean them and cycle the connection a few times.. I think it might be just a tiny bit of build up. Since they are built to such tight tolerances it wouldnt take more than a fine film to compromise the smoothness of the operation and increase resistance. Maybe Koolance should look into upping the spring rate a tad!