diff --git a/tests/test_bco_trainer.py b/tests/test_bco_trainer.py
index a2a625d1e74..e74b3f15f94 100644
--- a/tests/test_bco_trainer.py
+++ b/tests/test_bco_trainer.py
@@ -194,9 +194,9 @@ def test_tokenize_and_process_tokens(self):
                 batched=True,
                 batch_size=2,
             )
-            self.assertListEqual(tokenized_dataset["prompt"], dataset["prompt"])
-            self.assertListEqual(tokenized_dataset["completion"], dataset["completion"])
-            self.assertListEqual(tokenized_dataset["label"], dataset["label"])
+            self.assertListEqual(tokenized_dataset["prompt"][:], dataset["prompt"][:])
+            self.assertListEqual(tokenized_dataset["completion"][:], dataset["completion"][:])
+            self.assertListEqual(tokenized_dataset["label"][:], dataset["label"][:])
             self.assertListEqual(tokenized_dataset["prompt_input_ids"][0], [46518, 374, 2664, 1091])
             self.assertListEqual(tokenized_dataset["prompt_attention_mask"][0], [1, 1, 1, 1])
             self.assertListEqual(tokenized_dataset["answer_input_ids"][0], [27261, 13])
@@ -212,9 +212,9 @@ def test_tokenize_and_process_tokens(self):
                 "max_prompt_length": trainer.max_prompt_length,
             }
             processed_dataset = tokenized_dataset.map(_process_tokens, fn_kwargs=fn_kwargs)
-            self.assertListEqual(processed_dataset["prompt"], dataset["prompt"])
-            self.assertListEqual(processed_dataset["completion"], dataset["completion"])
-            self.assertListEqual(processed_dataset["label"], dataset["label"])
+            self.assertListEqual(processed_dataset["prompt"][:], dataset["prompt"][:])
+            self.assertListEqual(processed_dataset["completion"][:], dataset["completion"][:])
+            self.assertListEqual(processed_dataset["label"][:], dataset["label"][:])
             self.assertListEqual(processed_dataset["prompt_input_ids"][0], [46518, 374, 2664, 1091])
             self.assertListEqual(processed_dataset["prompt_attention_mask"][0], [1, 1, 1, 1])
             self.assertListEqual(
diff --git a/tests/test_kto_trainer.py b/tests/test_kto_trainer.py
index 140467fc87b..54fe23ee298 100644
--- a/tests/test_kto_trainer.py
+++ b/tests/test_kto_trainer.py
@@ -153,9 +153,9 @@ def test_tokenize_and_process_tokens(self):
                 batched=True,
                 batch_size=2,
             )
-            self.assertListEqual(tokenized_dataset["prompt"], train_dataset["prompt"])
-            self.assertListEqual(tokenized_dataset["completion"], train_dataset["completion"])
-            self.assertListEqual(tokenized_dataset["label"], train_dataset["label"])
+            self.assertListEqual(tokenized_dataset["prompt"][:], train_dataset["prompt"][:])
+            self.assertListEqual(tokenized_dataset["completion"][:], train_dataset["completion"][:])
+            self.assertListEqual(tokenized_dataset["label"][:], train_dataset["label"][:])
             self.assertListEqual(tokenized_dataset["prompt_input_ids"][0], [46518, 374, 2664, 1091])
             self.assertListEqual(tokenized_dataset["prompt_attention_mask"][0], [1, 1, 1, 1])
             self.assertListEqual(tokenized_dataset["answer_input_ids"][0], [27261, 13])
@@ -193,9 +193,9 @@ def test_tokenize_and_process_tokens(self):
                 "max_prompt_length": trainer.max_prompt_length,
             }
             processed_dataset = tokenized_dataset.map(_process_tokens, fn_kwargs=fn_kwargs, num_proc=2)
-            self.assertListEqual(processed_dataset["prompt"], train_dataset["prompt"])
-            self.assertListEqual(processed_dataset["completion"], train_dataset["completion"])
-            self.assertListEqual(processed_dataset["label"], train_dataset["label"])
+            self.assertListEqual(processed_dataset["prompt"][:], train_dataset["prompt"][:])
+            self.assertListEqual(processed_dataset["completion"][:], train_dataset["completion"][:])
+            self.assertListEqual(processed_dataset["label"][:], train_dataset["label"][:])
             self.assertListEqual(processed_dataset["prompt_input_ids"][0], [46518, 374, 2664, 1091])
             self.assertListEqual(processed_dataset["prompt_attention_mask"][0], [1, 1, 1, 1])
             self.assertListEqual(
diff --git a/trl/trainer/iterative_sft_trainer.py b/trl/trainer/iterative_sft_trainer.py
index 853d126429b..36c866c9961 100644
--- a/trl/trainer/iterative_sft_trainer.py
+++ b/trl/trainer/iterative_sft_trainer.py
@@ -357,6 +357,13 @@ def step(
                 "No 'labels' or 'text_labels' are provided. When using an encoder-decoder architecture, 'labels' or 'text_labels' must be passed."
             )
 
+        # Convert Column to list if not already
+        input_ids = input_ids[:] if input_ids is not None else None
+        attention_mask = attention_mask[:] if attention_mask is not None else None
+        labels = labels[:] if labels is not None else None
+        texts = texts[:] if texts is not None else None
+        texts_labels = texts_labels[:] if texts_labels is not None else None
+
         input_ids, attention_mask, labels, texts, texts_labels = self._step_safety_checker(
             input_ids, attention_mask, labels, texts, texts_labels
         )