Wireshark filtering out ONLY telnet?

Okay, so I have an oddball problem that I'm at a loss for.

I have a Cisco switch on my desk and I've set up a monitor port such that my laptop can see the sessions going in and out of my desktop. (Laptop is obviously running Wireshark.)

When I ping an external device from my desktop, I see all the packets associated with the ICMP. When I point my browser to the external entity, I see all those packets. However, when I telnet to the external device, I never see the telnet packets. Telnet works and I get to the host just fine. I just don't see them in Wireshark.

I have no capture or display filters in place... At all. I've done a complete uninstall of Wireshark (including settings) and reinstalled. For some reason my system is either dropping these or filtering them somewhere I can't find. Coworker's laptop with Wireshark sees the packets just fine. Thoughts? What the heck is going on with my system / install?