diff --git a/core/modules/block/src/Plugin/migrate/process/BlockPluginId.php b/core/modules/block/src/Plugin/migrate/process/BlockPluginId.php
index 08525674e3..64d179c93d 100644
--- a/core/modules/block/src/Plugin/migrate/process/BlockPluginId.php
+++ b/core/modules/block/src/Plugin/migrate/process/BlockPluginId.php
@@ -52,6 +52,7 @@ public static function create(ContainerInterface $container, array $configuratio
         'd6_custom_block',
         'd7_custom_block',
       ],
+      'return_associative' => TRUE,
     ];
     return new static(
       $configuration,
@@ -84,7 +85,7 @@ public function transform($value, MigrateExecutableInterface $migrate_executable
             $block_id = $this->migrationPlugin
               ->transform($delta, $migrate_executable, $row, $destination_property);
             if ($block_id) {
-              return 'block_content:' . $this->blockContentStorage->load($block_id)->uuid();
+              return 'block_content:' . $this->blockContentStorage->load($block_id['id'])->uuid();
             }
           }
           break;
diff --git a/core/modules/block/src/Plugin/migrate/process/BlockVisibility.php b/core/modules/block/src/Plugin/migrate/process/BlockVisibility.php
index 271edd48c3..3e2c71e109 100644
--- a/core/modules/block/src/Plugin/migrate/process/BlockVisibility.php
+++ b/core/modules/block/src/Plugin/migrate/process/BlockVisibility.php
@@ -64,6 +64,7 @@ public static function create(ContainerInterface $container, array $configuratio
         'd6_user_role',
         'd7_user_role',
       ],
+      'return_associative' => TRUE,
     ];
     return new static(
       $configuration,
@@ -94,7 +95,7 @@ public function transform($value, MigrateExecutableInterface $migrate_executable
       ];
 
       foreach ($roles as $key => $role_id) {
-        $roles[$key] = $this->migrationPlugin->transform($role_id, $migrate_executable, $row, $destination_property);
+        $roles[$key] = $this->migrationPlugin->transform($role_id, $migrate_executable, $row, $destination_property)['id'];
       }
       $visibility['user_role']['roles'] = array_combine($roles, $roles);
     }
diff --git a/core/modules/comment/migrations/d6_comment.yml b/core/modules/comment/migrations/d6_comment.yml
index dc8aecebec..6875beca0b 100644
--- a/core/modules/comment/migrations/d6_comment.yml
+++ b/core/modules/comment/migrations/d6_comment.yml
@@ -36,7 +36,7 @@ process:
     -
       plugin: extract
       index:
-      - id
+        - id
   field_name: '@comment_type'
   subject: subject
   uid: uid
diff --git a/core/modules/comment/migrations/d6_comment_entity_display.yml b/core/modules/comment/migrations/d6_comment_entity_display.yml
index ff50d4de0e..c9a039e7a9 100644
--- a/core/modules/comment/migrations/d6_comment_entity_display.yml
+++ b/core/modules/comment/migrations/d6_comment_entity_display.yml
@@ -26,7 +26,7 @@ process:
     -
       plugin: extract
       index:
-      - id
+        - id
   view_mode: 'constants/view_mode'
   options: 'constants/options'
   bundle: type
diff --git a/core/modules/comment/migrations/d6_comment_entity_form_display.yml b/core/modules/comment/migrations/d6_comment_entity_form_display.yml
index 47102505e7..3c151607cb 100644
--- a/core/modules/comment/migrations/d6_comment_entity_form_display.yml
+++ b/core/modules/comment/migrations/d6_comment_entity_form_display.yml
@@ -25,7 +25,7 @@ process:
     -
       plugin: extract
       index:
-      - id
+        - id
   form_mode: 'constants/form_mode'
   options: 'constants/options'
   bundle: type
diff --git a/core/modules/comment/migrations/d6_comment_entity_form_display_subject.yml b/core/modules/comment/migrations/d6_comment_entity_form_display_subject.yml
index ab6fd716ce..99ab674523 100644
--- a/core/modules/comment/migrations/d6_comment_entity_form_display_subject.yml
+++ b/core/modules/comment/migrations/d6_comment_entity_form_display_subject.yml
@@ -29,7 +29,7 @@ process:
     -
       plugin: extract
       index:
-      - id
+        - id
   hidden:
     plugin: static_map
     source: comment_subject_field
diff --git a/core/modules/comment/migrations/d6_comment_field_instance.yml b/core/modules/comment/migrations/d6_comment_field_instance.yml
index f217432456..83bb1a9cc1 100644
--- a/core/modules/comment/migrations/d6_comment_field_instance.yml
+++ b/core/modules/comment/migrations/d6_comment_field_instance.yml
@@ -25,7 +25,7 @@ process:
     -
       plugin: extract
       index:
-      - id
+        - id
   bundle: type
   'default_value/0/status':
     # We're using static_map instead of default_value otherwise if the source
diff --git a/core/modules/comment/migrations/d7_comment.yml b/core/modules/comment/migrations/d7_comment.yml
index a6434a6675..812567c224 100644
--- a/core/modules/comment/migrations/d7_comment.yml
+++ b/core/modules/comment/migrations/d7_comment.yml
@@ -37,7 +37,7 @@ process:
     -
       plugin: extract
       index:
-      - id
+        - id
   field_name: '@comment_type'
   subject: subject
   uid: uid
diff --git a/core/modules/comment/migrations/d7_comment_entity_form_display.yml b/core/modules/comment/migrations/d7_comment_entity_form_display.yml
index c4ec9671bc..6581a0e6bb 100644
--- a/core/modules/comment/migrations/d7_comment_entity_form_display.yml
+++ b/core/modules/comment/migrations/d7_comment_entity_form_display.yml
@@ -25,7 +25,7 @@ process:
     -
       plugin: extract
       index:
-      - id
+        - id
   form_mode: 'constants/form_mode'
   options: 'constants/options'
   bundle: type
diff --git a/core/modules/comment/migrations/d7_comment_entity_form_display_subject.yml b/core/modules/comment/migrations/d7_comment_entity_form_display_subject.yml
index b302c017c8..58099737e9 100644
--- a/core/modules/comment/migrations/d7_comment_entity_form_display_subject.yml
+++ b/core/modules/comment/migrations/d7_comment_entity_form_display_subject.yml
@@ -29,7 +29,7 @@ process:
     -
       plugin: extract
       index:
-      - id
+        - id
   hidden:
     plugin: static_map
     source: comment_subject_field
diff --git a/core/modules/comment/migrations/d7_comment_field.yml b/core/modules/comment/migrations/d7_comment_field.yml
index 885055bf04..1ba0346528 100644
--- a/core/modules/comment/migrations/d7_comment_field.yml
+++ b/core/modules/comment/migrations/d7_comment_field.yml
@@ -22,7 +22,7 @@ process:
     -
       plugin: extract
       index:
-      - field_name
+        - id
   type: 'constants/type'
   'settings/comment_type': '@field_name'
 destination:
diff --git a/core/modules/comment/migrations/d7_comment_field_instance.yml b/core/modules/comment/migrations/d7_comment_field_instance.yml
index 09716b9997..920235c923 100644
--- a/core/modules/comment/migrations/d7_comment_field_instance.yml
+++ b/core/modules/comment/migrations/d7_comment_field_instance.yml
@@ -25,7 +25,7 @@ process:
     -
       plugin: extract
       index:
-      - id
+        - id
   bundle: type
   'default_value/0/status':
     # We're using static_map instead of default_value otherwise if the source
diff --git a/core/modules/migrate/src/Plugin/migrate/process/MenuLinkParent.php b/core/modules/migrate/src/Plugin/migrate/process/MenuLinkParent.php
index 2d33e3abe3..62b537d349 100644
--- a/core/modules/migrate/src/Plugin/migrate/process/MenuLinkParent.php
+++ b/core/modules/migrate/src/Plugin/migrate/process/MenuLinkParent.php
@@ -52,7 +52,10 @@ public function __construct(array $configuration, $plugin_id, $plugin_definition
    * {@inheritdoc}
    */
   public static function create(ContainerInterface $container, array $configuration, $plugin_id, $plugin_definition, MigrationInterface $migration = NULL) {
-    $migration_configuration['migration'][] = $migration->id();
+    $migration_configuration = [
+      'migration' => $migration->id(),
+      'return_associative' => TRUE,
+    ];
     return new static(
       $configuration,
       $plugin_id,
@@ -78,7 +81,7 @@ public function transform($value, MigrateExecutableInterface $migrate_executable
       $already_migrated_id = $this
         ->migrationPlugin
         ->transform($parent_id, $migrate_executable, $row, $destination_property);
-      if ($already_migrated_id && ($link = $this->menuLinkStorage->load($already_migrated_id))) {
+      if ($already_migrated_id && ($link = $this->menuLinkStorage->load($already_migrated_id['id']))) {
         return $link->getPluginId();
       }
     }
diff --git a/core/modules/user/migrations/d7_user.yml b/core/modules/user/migrations/d7_user.yml
index 5aa1c25529..aeb0378b0e 100644
--- a/core/modules/user/migrations/d7_user.yml
+++ b/core/modules/user/migrations/d7_user.yml
@@ -39,9 +39,9 @@ process:
       source: roles
       return_associative: TRUE
     -
-      plugin: extract
-      index:
-        - id
+      plugin: sub_process
+      process:
+        target_id: id
   user_picture:
     -
       plugin: default_value