diff -u b/core/modules/link/lib/Drupal/link/Plugin/field/formatter/LinkFormatter.php b/core/modules/link/lib/Drupal/link/Plugin/field/formatter/LinkFormatter.php
--- b/core/modules/link/lib/Drupal/link/Plugin/field/formatter/LinkFormatter.php
+++ b/core/modules/link/lib/Drupal/link/Plugin/field/formatter/LinkFormatter.php
@@ -133,11 +133,15 @@
 
         // Add optional 'rel' attribute to link options.
         if (!empty($settings['rel'])) {
-          $item->options['attributes']['rel'] = $settings['rel'];
+          $options = $item->options;
+          $options['attributes']['rel'] = $settings['rel'];
+          $item->options = $options;
         }
         // Add optional 'target' attribute to link options.
         if (!empty($settings['target'])) {
-          $item->options['attributes']['target'] = $settings['target'];
+          $options = $item->options;
+          $options['attributes']['target'] = $settings['target'];
+          $item->options = $options;
         }
       }
     }