diff --git a/system/Config/BaseService.php b/system/Config/BaseService.php
index 483da962d5ad..579879e9c768 100644
--- a/system/Config/BaseService.php
+++ b/system/Config/BaseService.php
@@ -445,8 +445,9 @@ public static function resetSingle(string $name)
      */
     public static function injectMock(string $name, $mock)
     {
-        static::$instances[$name]         = $mock;
-        static::$mocks[strtolower($name)] = $mock;
+        $name                     = strtolower($name);
+        static::$instances[$name] = $mock;
+        static::$mocks[$name]     = $mock;
     }
 
     /**
diff --git a/user_guide_src/source/changelogs/v4.7.4.rst b/user_guide_src/source/changelogs/v4.7.4.rst
index 1373f9fa1720..1cf22169f347 100644
--- a/user_guide_src/source/changelogs/v4.7.4.rst
+++ b/user_guide_src/source/changelogs/v4.7.4.rst
@@ -35,6 +35,7 @@ Bugs Fixed
 - **Common:** Fixed a bug in ``env()`` where a ``TypeError`` could be thrown when non-string values were passed.
 - **Common:** Fixed ``esc()`` to propagate encoding correctly and prevent reference leaks.
 - **Commands:** Fixed a bug where ``spark lang:find`` treated translation keys already provided by the framework or another namespace (such as ``Errors.*`` in ``system/Language``) as new, listing them under ``--show-new`` and writing untranslated placeholders into ``app/Language`` that overrode the existing translations.
+- **Config:** Fixed a bug where ``BaseService::injectMock`` did not apply ``strtolower`` consistently, causing inconsistent Service and Mock registration and resolution.
 - **Database:** Fixed a bug where ``updateBatch()`` could be called after Query Builder ``where()`` conditions, even though it's not supported. In this situation, now the ``DatabaseException`` is thrown.
 - **Filters:** Fixed a bug in ``InvalidChars`` filter where invalid UTF-8 or control characters in array keys were not checked.
 - **HTTP:** Fixed a bug where the User Agent library reported Safari's WebKit version instead of the browser version from the ``Version`` token.