Hey there. When 'Bungie Names' were introduced, our Bungie Name was set as the same name as the first platform account we logged in with. If for some reason that name trips the name filter, we get a default 'Guardian' name instead. I see your Steam name is being censored when I look at your profile. That is likely the reason you were given a default name, and also since that name has already been rejected, that is why you can't manually change it back to that using a name change. You'll have to go with something else.