The switch interface shows 89,920 collisions, which is a strong indicator of a duplex mismatch.
This typically occurs when one end of the connection (in this case, the NIC on the employee's laptop) is set to half duplex, while the switch port is operating in full duplex.
In half duplex, devices must wait for the line to be clear before transmitting, which leads to collisions if both try to transmit simultaneously. High collisions and performance issues are classic symptoms.
Faulty patch cords often result in CRC errors or physical link problems, not just high collisions.
Switchport bandwidth isn't the issue here - collisions, not congestion, are the root cause.
Multicast misconfiguration would affect group traffic, not cause collisions on a single port. So the correct diagnosis is duplex mismatch, most likely from the NIC being set to half duplex.