diff --git a/ckan/logic/schema.py b/ckan/logic/schema.py
index b265a9df5e0..284d9f2e677 100644
--- a/ckan/logic/schema.py
+++ b/ckan/logic/schema.py
@@ -211,8 +211,8 @@ def default_show_package_schema():
         'format': [ignore_missing, clean_format, unicode],
         'created': [ignore_missing],
         'position': [not_empty],
-        'last_modified': [ignore_missing],
-        'cache_last_updated': [ignore_missing],
+        'last_modified': [],
+        'cache_last_updated': [],
         'revision_id': [],
         'package_id': [],
         'size': [],