diff --git a/src/lighteval/logging/evaluation_tracker.py b/src/lighteval/logging/evaluation_tracker.py
index 2694bae81..63fe99e8a 100644
--- a/src/lighteval/logging/evaluation_tracker.py
+++ b/src/lighteval/logging/evaluation_tracker.py
@@ -214,7 +214,7 @@ def save(self) -> None:
         details_datasets: dict[str, Dataset] = {}
         for task_name, task_details in self.details_logger.details.items():
             # Create a dataset from the dictionary - we force cast to str to avoid formatting problems for nested objects
-            dataset = Dataset.from_list([asdict(detail) for detail in task_details])
+            dataset = Dataset.from_list([{k: str(v) for k, v in asdict(detail).items()} for detail in task_details])
 
             # We don't keep 'id' around if it's there
             column_names = dataset.column_names