diff --git a/torchrl/objectives/cql.py b/torchrl/objectives/cql.py
index 268be721235..86d5461b15f 100644
--- a/torchrl/objectives/cql.py
+++ b/torchrl/objectives/cql.py
@@ -511,14 +511,10 @@ def forward(self, tensordict: TensorDictBase) -> TensorDictBase:
         loss_actor_bc, bc_metadata = self.actor_bc_loss(td_device)
         loss_actor, actor_metadata = self.actor_loss(td_device)
         loss_alpha, alpha_metadata = self.alpha_loss(td_device)
-        metadata.update(
-            {
-                **bc_metadata,
-                **cql_metadata,
-                **actor_metadata,
-                **alpha_metadata,
-            }
-        )
+        metadata.update(bc_metadata)
+        metadata.update(cql_metadata)
+        metadata.update(actor_metadata)
+        metadata.update(alpha_metadata)
         tensordict_reshape.set(
             self.tensor_keys.priority, metadata.pop("td_error").detach().max(0).values
         )