diff --git a/tensordict/_td.py b/tensordict/_td.py
index 57529590d..73dd4d800 100644
--- a/tensordict/_td.py
+++ b/tensordict/_td.py
@@ -2579,7 +2579,7 @@ def _set_at_str(self, key, value, idx, *, validated, non_blocking: bool):
                     ignore_lock=True,
                 )
             is_diff = dest[idx].tolist() != value.tolist()
-            if is_diff:
+            if is_diff.any():
                 dest_val = dest.maybe_to_stack()
                 dest_val[idx] = value
                 if dest_val is not dest: