diff --git a/tests/models/test_taskinstance.py b/tests/models/test_taskinstance.py
index c2993e9ce8d95..2d3da6a413e2a 100644
--- a/tests/models/test_taskinstance.py
+++ b/tests/models/test_taskinstance.py
@@ -1539,8 +1539,9 @@ def do_something_else(i):
         monkeypatch.setattr(_UpstreamTIStates, "calculate", lambda *_: upstream_states)
         ti = dr.get_task_instance("do_something_else", session=session)
         ti.map_index = 0
+        base_task = ti.task
         for map_index in range(1, 5):
-            ti = TaskInstance(dr.task_instances[-1].task, run_id=dr.run_id, map_index=map_index)
+            ti = TaskInstance(base_task, run_id=dr.run_id, map_index=map_index)
             session.add(ti)
             ti.dag_run = dr
         session.flush()