diff --git a/example/tests/integration/test_polymorphism.py b/example/tests/integration/test_polymorphism.py
index 116243f1..836a9046 100644
--- a/example/tests/integration/test_polymorphism.py
+++ b/example/tests/integration/test_polymorphism.py
@@ -50,7 +50,6 @@ def test_polymorphism_on_included_relations(single_company, client):
         for rel in content["data"]["relationships"]["futureProjects"]["data"]
     } == {"researchProjects", "artProjects"}
     assert {x.get("type") for x in content.get("included")} == {
-        "artProjects",
         "artProjects",
         "researchProjects",
     }, "Detail included types are incorrect"