diff --git a/core/lib/Drupal/Core/Extension/ThemeHandler.php b/core/lib/Drupal/Core/Extension/ThemeHandler.php
index c3805eb..a4a086a 100644
--- a/core/lib/Drupal/Core/Extension/ThemeHandler.php
+++ b/core/lib/Drupal/Core/Extension/ThemeHandler.php
@@ -407,7 +407,7 @@ public function refreshInfo() {
     $list = $this->rebuildThemeData();
     foreach ($list as $name => $theme) {
       if (isset($enabled[$name])) {
-        $this->list[$name] = $this->addTheme($theme);
+        $this->addTheme($theme);
       }
     }
     $this->state->set('system.theme.data', $this->list);