diff -u b/core/modules/content_translation/migration_templates/d6_i18n_block.yml b/core/modules/content_translation/migration_templates/d6_i18n_block.yml
--- b/core/modules/content_translation/migration_templates/d6_i18n_block.yml
+++ b/core/modules/content_translation/migration_templates/d6_i18n_block.yml
@@ -11,18 +11,11 @@
   property: constants/dest_label
   translation: title
   id:
-    -
-      plugin: concat
-      source:
-        - module
-        - delta
-      delimiter: _
-    -
-      plugin: substr
-      length: 32
-  configuration_name: @id
-  element_name: constance/dest_label
-  value: title
+    plugin: migration
+    migration: d6_block
+    source:
+      - module
+      - delta
   plugin:
     -
       plugin: static_map
only in patch2:
unchanged:
--- a/core/modules/block/tests/src/Kernel/Migrate/d6/MigrateBlockTest.php
+++ b/core/modules/block/tests/src/Kernel/Migrate/d6/MigrateBlockTest.php
@@ -102,7 +102,7 @@ public function testBlockMigration() {
     $this->assertEntity('user', $visibility, 'sidebar_first', 'bartik', 0, '', '0');
 
     $visibility = [];
-    $this->assertEntity('user_1', $visibility, 'sidebar_first', 'bartik', 0, '', '0');
+    $this->assertEntity('user_1', $visibility, 'sidebar_first', 'bartik', 0, 'zu - Test Title 02', 'visible');
 
     $visibility['user_role']['id'] = 'user_role';
     $roles['authenticated'] = 'authenticated';