host_name default has to use a proc, apparently file is read before dotenv-rails changes environment

config/constants/settings/definition.rb

@@ -537,7 +537,7 @@ module Settings
       },
       host_name: {
         format: :string,
-        default: "#{ENV.fetch('HOST', 'localhost')}:#{ENV.fetch('PORT', 3000)}",
+        default: -> { "#{ENV.fetch('HOST', 'localhost')}:#{ENV.fetch('PORT', 3000)}" },
         default_by_env: {
           # We do not want to set a localhost host name in production
           production: nil