diff --git a/src/Symfony/Bundle/FrameworkBundle/DependencyInjection/Configuration.php b/src/Symfony/Bundle/FrameworkBundle/DependencyInjection/Configuration.php
index <HASH>..<HASH> 100644
--- a/src/Symfony/Bundle/FrameworkBundle/DependencyInjection/Configuration.php
+++ b/src/Symfony/Bundle/FrameworkBundle/DependencyInjection/Configuration.php
@@ -1114,6 +1114,7 @@ class Configuration implements ConfigurationInterface
                     ->end()
                     ->children()
                         ->arrayNode('routing')
+                            ->normalizeKeys(false)
                             ->useAttributeAsKey('message_class')
                             ->beforeNormalization()
                                 ->always()
@@ -1173,6 +1174,7 @@ class Configuration implements ConfigurationInterface
                             ->end()
                         ->end()
                         ->arrayNode('transports')
+                            ->normalizeKeys(false)
                             ->useAttributeAsKey('name')
                             ->arrayPrototype()
                                 ->beforeNormalization()
@@ -1220,6 +1222,7 @@ class Configuration implements ConfigurationInterface
                         ->scalarNode('default_bus')->defaultNull()->end()
                         ->arrayNode('buses')
                             ->defaultValue(['messenger.bus.default' => ['default_middleware' => true, 'middleware' => []]])
+                            ->normalizeKeys(false)
                             ->useAttributeAsKey('name')
                             ->arrayPrototype()
                                 ->addDefaultsIfNotSet()
[Messenger] fix broken key normalization