The banner is glitched, always showing one person on the server even though the server is empty.

I would assume it shows the last person to leave.

It shows this until the next person joins the server which will change the name.

If the server is empty for hours, days, weeks, months, the name is always there.

This problem doesn't appear to be affecting most of our other America's Army 3 Servers.

I'm assuming you are referring to this server http://www.gametracker.com/server_info/208.77.144.50:8777/.

It appears that this problem only started a few days ago.

http://cache.www.gametracker.com/images/graphs/server_players.php?GSID=847269&start=-1w&request=025894246754830885

Did anything change recently on this server that may have caused the issue?

Is the server up to date with all patches/fixes?

Are there any custom mods running on the server?

You can try restarting the server to see if that fixes the problem.