diff --git a/core/lib/Drupal/Core/Extension/ModuleHandler.php b/core/lib/Drupal/Core/Extension/ModuleHandler.php
index 2134420..5c4d37d 100644
--- a/core/lib/Drupal/Core/Extension/ModuleHandler.php
+++ b/core/lib/Drupal/Core/Extension/ModuleHandler.php
@@ -90,6 +90,13 @@ class ModuleHandler implements ModuleHandlerInterface {
   protected $root;
 
   /**
+   * A list of module include file keys.
+   *
+   * @var array
+   */
+  protected $includeFileKeys = [];
+
+  /**
    * Constructs a ModuleHandler object.
    *
    * @param string $root
@@ -257,7 +264,6 @@ public function loadAllIncludes($type, $name = NULL) {
    * {@inheritdoc}
    */
   public function loadInclude($module, $type, $name = NULL) {
-    static $files = [];
 
     if ($type == 'install') {
       // Make sure the installation API is available
@@ -266,18 +272,18 @@ public function loadInclude($module, $type, $name = NULL) {
 
     $name = $name ?: $module;
     $key = $type . ':' . $module . ':' . $name;
-    if (!isset($files[$key])) {
-      $files[$key] = FALSE;
+    if (!isset($this->includeFileKeys[$key])) {
+      $this->includeFileKeys[$key] = FALSE;
       if (isset($this->moduleList[$module])) {
         $file = $this->root . '/' . $this->moduleList[$module]->getPath() . "/$name.$type";
         if (is_file($file)) {
           require_once $file;
-          $files[$key] = $file;
+          $this->includeFileKeys[$key] = $file;
         }
       }
     }
 
-    return $files[$key];
+    return $this->includeFileKeys[$key];
   }
 
   /**