diff --git a/src/lerobot/configs/policies.py b/src/lerobot/configs/policies.py
index 7532f061..9a2bb911 100644
--- a/src/lerobot/configs/policies.py
+++ b/src/lerobot/configs/policies.py
@@ -196,11 +196,10 @@ class PreTrainedConfig(draccus.ChoiceRegistry, HubMixin, abc.ABC):
             config = json.load(f)
 
         config.pop("type")
-        with tempfile.NamedTemporaryFile("w+") as f:
+        with tempfile.NamedTemporaryFile("w+", delete=False, suffix=".json") as f:
             json.dump(config, f)
             config_file = f.name
-            f.flush()
 
-            cli_overrides = policy_kwargs.pop("cli_overrides", [])
-            with draccus.config_type("json"):
-                return draccus.parse(orig_config.__class__, config_file, args=cli_overrides)
+        cli_overrides = policy_kwargs.pop("cli_overrides", [])
+        with draccus.config_type("json"):
+            return draccus.parse(orig_config.__class__, config_file, args=cli_overrides)
diff --git a/src/lerobot/policies/pretrained.py b/src/lerobot/policies/pretrained.py
index 2f69309c..b770c980 100644
--- a/src/lerobot/policies/pretrained.py
+++ b/src/lerobot/policies/pretrained.py
@@ -246,7 +246,9 @@ class PreTrainedPolicy(nn.Module, HubMixin, abc.ABC):
             base_model=base_model,
         )
 
-        template_card = files("lerobot.templates").joinpath("lerobot_modelcard_template.md").read_text()
+        template_card = (
+            files("lerobot.templates").joinpath("lerobot_modelcard_template.md").read_text(encoding="utf-8")
+        )
         card = ModelCard.from_template(card_data, template_str=template_card)
         card.validate()
         return card