I've added a second server manager instance on a physical machine.
The Server Manager uses a file called BrokerServerList.xml in ~\App_Data directory to save information on APM Servers. If you copied that, it will show up in the second Server Manager. You can delete it and it will be recreated when an APM Server connects to that Server Manager. Entries that aren't used (ie: APM Servers that don't connect for a period of time) will be automatically dropped. I think the period of time after which stale servers are deleted is 7 days.
Note that a given APM Server can only talk to one Server Manager (as configured in settings), unless you've set up an active/active load balancer for the Server Managers.
Answer Verified By: Rick Flaviano
Thank you! That corrected the issue.