diff --git a/ippisite/ippidb/models.py b/ippisite/ippidb/models.py
index b8e5042985f66dcbe420ece1da4545fad39fb003..8f233f8691f1163e1fc736b85ee81529312c7d42 100644
--- a/ippisite/ippidb/models.py
+++ b/ippisite/ippidb/models.py
@@ -895,6 +895,11 @@ class Compound(AutoFillableModel):
         return self.drugbankcompoundtanimoto_set.order_by("-tanimoto")
 
     def is_validated(self):
+        # if compound is not linked to any CompoundAction this is
+        # because it was dereferenced because of duplication by
+        # `replace_compound_references`
+        if self.compoundaction_set.count()==0:
+            return False
         for ca in self.compoundaction_set.all():
             if ca.ppi.contribution_set.filter(validated=False).exists():
                 return False