Update to Drupal 8.0.0-beta15. For more information, see: https://www.drupal.org/node/2563023

core/modules/block_content/config/optional/views.view.block_content.yml

@@ -8,7 +8,7 @@ id: block_content
 label: 'Custom block library'
 module: views
 description: 'Find and manage custom blocks.'
-tag: ''
+tag: default
 base_table: block_content_field_data
 base_field: id
 core: 8.x
@@ -290,12 +290,14 @@ display:
           hide_empty: false
           empty_zero: false
           hide_alter_empty: true
-          date_format: short
-          custom_date_format: ''
-          timezone: ''
           entity_type: block_content
           entity_field: changed
-          plugin_id: date
+          type: timestamp
+          settings:
+            date_format: short
+            custom_date_format: ''
+            timezone: ''
+          plugin_id: field
         operations:
           id: operations
           table: block_content