Brutus Not In Boss Arena

I can't even tell if this is a bug or something but when I went to go fight Brutus he was not in the boss arena area but actually the area before it next to the door to go to the arena. I don't think this is supposed to happen so that's why I'm sharing it https://cdn.discordapp.com/attachments/788582612951367702/868964413892329532/screenshot-0000.png
This is the loot from him. Feel free to delete this if it is intentional or already known :)