Thanks for the reply. I turned it off as soon as I saw that it was enabled everywhere. It definitely caused an issue on our network, so I was trying to understand better what it did.
Where I'm confused is it was configured as an access port using VLAN 1. VLAN 1 is disabled on the trunks going to the controller and from what I can tell internally on the controller too.
The APs were definitely taking Ethernet frames from the edge switch VLANs and tunneling it back to the controller. Once it gets to the controller, does the controller send the Ethernet frames back out to all of the APs configured with wired-AP on the same VLAN (VLAN 1 in this case)?