A technician installs a new workstation in a warehouse. The Ethernet cable runs from a switch in the IDF, through a cable tray, and terminates at a wall jack roughly 130 meters away. The workstation intermittently drops its link and negotiates at only 100 Mbps despite being connected to a Gigabit switch. A cable tester shows correct wiremap and no shorts or opens. What is the MOST likely cause?