Frame Check Sequence Recorded in STP

This evening I was preparing to teach day 2 of my TCP/IP Weapons School class at USENIX. I decided I wanted to get a trace of Spanning Tree Protocol (STP) so I connected back to a box in my lab and ran Tshark. When I brought the trace back to my desktop to view in Wireshark, I saw the following:

How/why Tshark capture the FCS for this frame? I looked at other traffic (i.e., non-STP traffic) and did not see a FCS. The only other interesting aspect of this frame is the fact that it is pure 802.3 and not 802.3 with a LLC SNAP header, like this CDP frame:

I usually see 802.3 with a LLC SNAP header or just Ethernet II.

Does anyone have any ideas?