diff --git a/lerobot/common/policies/normalize.py b/lerobot/common/policies/normalize.py
index bcbb68a0..9cc94b92 100644
--- a/lerobot/common/policies/normalize.py
+++ b/lerobot/common/policies/normalize.py
@@ -338,6 +338,7 @@ class NormalizeBuffer(nn.Module):
         _initialize_stats_buffers(self, features, norm_map, stats)
 
     def forward(self, batch: dict[str, Tensor]) -> dict[str, Tensor]:
+        batch = dict(batch)
         for key, ft in self.features.items():
             if key not in batch:
                 continue
@@ -386,6 +387,7 @@ class UnnormalizeBuffer(nn.Module):
         _initialize_stats_buffers(self, features, norm_map, stats)
 
     def forward(self, batch: dict[str, Tensor]) -> dict[str, Tensor]:
+        # batch = dict(batch)
         for key, ft in self.features.items():
             if key not in batch:
                 continue