diff --git a/python/lsst/daf/butler/datastores/chainedDatastore.py b/python/lsst/daf/butler/datastores/chainedDatastore.py
index 28986d7a23..fb19b52227 100644
--- a/python/lsst/daf/butler/datastores/chainedDatastore.py
+++ b/python/lsst/daf/butler/datastores/chainedDatastore.py
@@ -461,7 +461,7 @@ def put_new(self, inMemoryDataset: Any, ref: DatasetRef) -> Mapping[str, Dataset
         npermanent = 0
         nephemeral = 0
         stored_refs: dict[str, DatasetRef] = {}
-        for datastore, constraints in zip(self.datastores, self.datastoreConstraints):
+        for datastore, constraints in zip(self.datastores, self.datastoreConstraints, strict=True):
             if (
                 constraints is not None and not constraints.isAcceptable(ref)
             ) or not datastore.constraints.isAcceptable(ref):