Site-wide-conversation spam?

[KarlPro123]

Hi. Updated my forum to 1.13.2 today and now I'm getting weird site-wide-conversation spam, so some account somehow renames the conversation and it doesn't stop, maybe a bug? Külaline = like an unregistered account or something in my language. Tried restarting.

I figured if there was a way to disable this conversation alltogether but allow private messages etc?