[Request] Server nickname to stay when changed the username

So, the usernames on a server shouldn't change when the username is changed, if the members don't have the permission to change their own nickname. For example, I have the username "Wumpus" and I change it to "Wampus" , and if I don't have the change nickname permission it shouldn't change on the server. I don't know if it's already but at least for my server, when people change their username it also changes on the server even if they don't have permission to change their nickname.