Update to Drupal 8.1.9. For more information, see https://www.drupal.org/project/drupal/releases/8.1.9

core/modules/comment/src/Plugin/migrate/source/d6/CommentVariablePerCommentType.php

@@ -20,7 +20,7 @@ class CommentVariablePerCommentType extends CommentVariable {
     $return = array();
     foreach ($node_types as $node_type => $data) {
       // Only 2 comment types depending on subject field visibility.
-      if (empty($data['comment_subject_field'])) {
+      if (!empty($data['comment_subject_field'])) {
         // Default label and description should be set in migration.
         $return['comment'] = array(
           'comment_type' => 'comment',

core/modules/comment/tests/src/Kernel/Migrate/d7/MigrateCommentTest.php

@@ -40,7 +40,7 @@ class MigrateCommentTest extends MigrateDrupal7TestBase {
       ),
     ));
     $this->executeMigrations([
-      'd7_node:test_content_type',
+      'd7_node',
       'd7_comment_type',
       'd7_comment',
     ]);

core/modules/comment/tests/src/Unit/Migrate/d6/CommentVariablePerCommentTypeTest.php

@@ -24,10 +24,10 @@ class CommentVariablePerCommentTypeTest extends MigrateSqlSourceTestCase {
     // Each result will also include a label and description, but those are
     // static values set by the source plugin and don't need to be asserted.
     array(
-      'comment_type' => 'comment_no_subject',
+      'comment_type' => 'comment',
     ),
     array(
-      'comment_type' => 'comment',
+      'comment_type' => 'comment_no_subject',
     ),
   );