diff --git a/src/ifcopenshell-python/ifcopenshell/util/sequence.py b/src/ifcopenshell-python/ifcopenshell/util/sequence.py
index 166a3c3674..6d905766df 100644
--- a/src/ifcopenshell-python/ifcopenshell/util/sequence.py
+++ b/src/ifcopenshell-python/ifcopenshell/util/sequence.py
@@ -279,7 +279,7 @@ def get_task_work_schedule(task: ifcopenshell.entity_instance) -> Union[ifcopens
 
 
 def get_nested_tasks(task: ifcopenshell.entity_instance) -> list[ifcopenshell.entity_instance]:
-    return [object for rel in task.IsNestedBy or [] for object in rel.RelatedObjects]
+    return [object for rel in task.IsNestedBy or [] for object in rel.RelatedObjects if object.is_a("IfcTask")]
 
 
 def get_parent_task(task: ifcopenshell.entity_instance) -> Union[ifcopenshell.entity_instance, None]: