diff --git a/airflow-core/src/airflow/models/taskinstance.py b/airflow-core/src/airflow/models/taskinstance.py
index 0fb9e4e88d9e9..85b438ca0e61a 100644
--- a/airflow-core/src/airflow/models/taskinstance.py
+++ b/airflow-core/src/airflow/models/taskinstance.py
@@ -1005,7 +1005,10 @@ def get_dagrun(self, session: Session = NEW_SESSION) -> DagRun:
         :return: DagRun
         """
         info: Any = inspect(self)
-        if info.attrs.dag_run.loaded_value is not NO_VALUE:
+        # If dag_run is loaded and not None, return it.
+        # In early lifecycle phases (e.g. task_instance_mutation_hook),
+        # dag_run may be marked as loaded but still be None.
+        if info.attrs.dag_run.loaded_value is not NO_VALUE and self.dag_run is not None:
             if getattr(self, "task", None) is not None:
                 if TYPE_CHECKING:
                     assert self.task