diff --git a/src/azul/service/avro_pfb.py b/src/azul/service/avro_pfb.py
index 62f06cf35..df94f6037 100644
--- a/src/azul/service/avro_pfb.py
+++ b/src/azul/service/avro_pfb.py
@@ -338,6 +338,8 @@ def pfb_schema_from_anvil_schema(anvil_schema: JSON
     entity_types = []
     for table_schema in sorted(anvil_schema['tables'], key=itemgetter('name')):
         table_name = table_schema['name']
+        # FIXME: Improve handling of DUOS replicas
+        #        https://github.com/DataBiosphere/azul/issues/6139
         is_duos_type = table_name.removeprefix('anvil_') == BundleEntityType.duos.value
         entity_types.append(table_name)
         field_schemas = []