アプデ履歴見たら
・No Local Admin Filtering
・A new filter has been added to the Server Browser, to include or exclude the servers that have ever used the kick/ban functionalities from the WebAdmin tool.
・A new icon has also been added to the Server Browser list for these servers.
て書いてあったからウェブアドミンツールで手動でキックやらBANやらするとそのサーバーにローカル管理者のアイコンが付くってことっぽい