diff --git a/mistral/engine/tasks.py b/mistral/engine/tasks.py
index d879cc7ef..1edb7c281 100644
--- a/mistral/engine/tasks.py
+++ b/mistral/engine/tasks.py
@@ -1078,6 +1078,8 @@ def _get_input_dicts(self, with_items_values, prev_index=-1):
             ctx = {}
 
             index = prev_index + concurrency
+            if self.is_index_invalid(index):
+                return
 
             for k, v in with_items_values.items():
                 ctx.update({k: v[index]})
@@ -1098,6 +1100,19 @@ def _get_input_dicts(self, with_items_values, prev_index=-1):
             result.append((i, self._get_action_input(ctx)))
 
         return result
+    
+    def is_index_invalid(self, index):
+        with db_api.named_lock('with-items-%s' % self.task_ex.id):
+
+            indices = db_api.get_accepted_executions_indexes(
+                id=self.task_ex.id,
+                workflow=self.task_ex.spec.get('workflow'),
+                accepted=True
+            )
+
+            finished = [idx[0] for idx in indices]
+            
+            return index in finished
 
     def _get_with_items_context(self):
         return self.task_ex.runtime_context.get(