New Auto-Discovery ports fail on Cisco switch

I have several Cisco 4510 switches in my network. Recently, whenever I run an auto-discovery for new port activity, I run into a situation where a new sensor is created, but the sensor fails and errors out with the error message of "Could not identify port number." I find that if I remove all information from the description field for that port (Using the Cisco CI), the problem will clear up and the port can be located. But as soon as I enter any information into the description field on the switch itself, the PRTG readout fails. What is going on? I have to have these ports labeled for internal documentation.