[c-nsp] quick spanning tree question

[Cord MacLeod]

3 days ago traffic started showing up on the trunk port connecting my top of rack switches.  Each of these switches has it's own better trunk path to the root bridge.  I can't see why any traffic at all would traverse these links unless the other trunk on g0/45 was down, which it isn't.  Also, spanning tree doesn't claim any topology changes.

switch3#sh spanning-tree root port 
VLAN0001         GigabitEthernet0/45
VLAN0100         GigabitEthernet0/45
VLAN0101         GigabitEthernet0/45
VLAN0102         GigabitEthernet0/45
VLAN0120         GigabitEthernet0/45
VLAN0200         GigabitEthernet0/45
VLAN0231         GigabitEthernet0/45
VLAN0250         GigabitEthernet0/45
VLAN0321         GigabitEthernet0/45
VLAN0450         GigabitEthernet0/45
VLAN0777         GigabitEthernet0/45
VLAN0888         GigabitEthernet0/45
switch3#

All vlans read same the Root and Desg port.

VLAN0101
  Spanning tree enabled protocol ieee
  Root ID    Priority    24677
             Address     0017.e1d6.e111
             Cost        4
             Port        45 (GigabitEthernet0/45)
             Hello Time   2 sec  Max Age 20 sec  Forward Delay 15 sec

  Bridge ID  Priority    32869  (priority 32768 sys-id-ext 101)
             Address     001e.1494.4000
             Hello Time   2 sec  Max Age 20 sec  Forward Delay 15 sec
             Aging Time 300

Interface        Role Sts Cost      Prio.Nbr Type
---------------- ---- --- --------- -------- --------------------------------
Gi0/45           Root FWD 4         128.45   P2p 
Gi0/46           Desg FWD 4         128.46   P2p 

Any ideas?