diff --git a/core-bundle/contao/dca/tl_article.php b/core-bundle/contao/dca/tl_article.php
index <HASH>..<HASH> 100644
--- a/core-bundle/contao/dca/tl_article.php
+++ b/core-bundle/contao/dca/tl_article.php
@@ -687,7 +687,7 @@ class tl_article extends Backend
 			$arrSections = array_merge($arrSections, $arrCustom);
 		}
 
-		return array_unique($arrSections);
+		return array_values(array_unique($arrSections));
 	}
[Core] Correctly assign articles to columns (see #<I>)