This is the problem of a specific user or something else?

[Dev_Work (Aleksandr)]

Good afternoon! Help me figure out the forum. This is the problem of a specific user or something else?

[Dev_Work (Aleksandr)]

The users did not have a username and the system set automatic them?

[osioke (Osioke Itseuwa)]

Can you share more detail or context about what the image is about?

[Dev_Work (Aleksandr)]

https://site.example.com/u?name=f5c

information about users in the system (forum)

[codinghorror (Jeff Atwood)]

Did you have any weird third party plugins installed? I remember Babble doing something odd like this.

[Dev_Work (Aleksandr)]

yes, we have third party plugins installed, also Babble

[osioke (Osioke Itseuwa)]

Okay, try loading your site in safe mode, or uninstall Babble (and possibly other non-official plugins) one by one, reloading/rebuilding your Discourse app afterwards and see if any of these help.