diff --git a/lerobot/common/datasets/lerobot_dataset.py b/lerobot/common/datasets/lerobot_dataset.py
index 29d91c152a..54d851dba8 100644
--- a/lerobot/common/datasets/lerobot_dataset.py
+++ b/lerobot/common/datasets/lerobot_dataset.py
@@ -557,8 +557,8 @@ def __init__(
         self.episode_data_index = get_episode_data_index(self.meta.episodes, self.episodes)
 
         # Check timestamps
-        timestamps = torch.stack(self.hf_dataset["timestamp"]).numpy()
-        episode_indices = torch.stack(self.hf_dataset["episode_index"]).numpy()
+        timestamps = torch.tensor(self.hf_dataset["timestamp"]).numpy()
+        episode_indices = torch.tensor(self.hf_dataset["episode_index"]).numpy()
         ep_data_index_np = {k: t.numpy() for k, t in self.episode_data_index.items()}
         check_timestamps_sync(timestamps, episode_indices, ep_data_index_np, self.fps, self.tolerance_s)