diff --git a/lib/ansible/playbook/task.py b/lib/ansible/playbook/task.py
index 58788df65b4..44f76c1e134 100644
--- a/lib/ansible/playbook/task.py
+++ b/lib/ansible/playbook/task.py
@@ -197,7 +197,8 @@ class Task(Base, Conditional, Taggable, Become):
         if self._task_include:
             all_vars.update(self._task_include.get_vars())
 
-        all_vars.update(self.serialize())
+        if isinstance(self.args, dict):
+            all_vars.update(self.args)
 
         if 'tags' in all_vars:
             del all_vars['tags']