During a recent change we rebooted a 7210 controller with two different port channels (currently only a single member interface in each).
Following the reboot, one of the upstream switches placed its interface to the controller into an error disabled state (BPDU guard).
The only causes I can think of are:
1) Somehow the controller acts as a bridge during boot and the switches on either side 'see' each other
2) Even though STP is disabled globally on the controller, during boot it sends BPDUs somehow?
Has anyone ever seen this happen before?