@Fae Thank you for your response.

I have confirmed that Show Pending Devices is enabled. I believe I would not have been able to "see" the Access Points to adopt them otherwise.

I have worked through the steps in the "fails to discover" link as follows:

1: LED Status: LEDs are showing normal behavior. Clearly the switch is working because the traffic between the adopted WAPs and the controller passes through it.

2: IP addresses are known and confirmed.

3: I can ping the switch and access points from the controller.

4: Controller, switch and access points are on the same VLAN and subnet. No special configuration needed.

5: I am using Ubuntu. No Windows Defender firewall present. I have tried with the UFW firewall disabled on the Server and this did not make a difference. It seems logical that since the WAP discovery packets passed through the firewall the switch discovery packets would as well.

6: The discovery Utility appears to be a Windows program, and there are no Windows devices on this network.

I have worked through the "Management VLAN" link as follows:

1: VLAN 11 has been added on the Wired Networks page.

2: As above, devices all have confirmed IP Addresses

3: When I go to the Devices page the SG2008p switch does not show up so these steps are impossible, which led to my reaching out here in an effort to figure out why. When I select "Batch Config" the options are not clickable, probably because there are no switches listed.

@KocherJJ 

Have you access to switch on http from Controller ?

try to login and set inform address in the switch config.

deafult user and password is admin and admin

@shberge The controller itself does not have a browser. I can tunnel through the router and access the switch from my laptop over http. I have tried both with and without the Controller IP entered in the "Inform" box.

@KocherJJ 

Ok, strange thing. I have 6-7 off this switch and there no problem to adopt localy or from remote site.

Have you tryed to set dhcp option 138 to controller ip address?

I grabbed another switch and configured it to tag the traffic from the SG-2008P with the correct VLAN and put it between the controller and the SG-2008P. Once I did this the controller detected the switch and was able to adopt it. Once the adoption was complete I was able to remove the intermediate switch and the switch synced up to the controller again when I connected it directly.

This certainly seems like a bug to me. I don't understand why I can't adopt it after connecting to a factory default switch and adding the VLAN. It would appear that it will only "discover" the controller over the default VLAN on the current firmware version.