diff --git a/nemo_aligner/data/nlp/builders.py b/nemo_aligner/data/nlp/builders.py
index 43d9231ef..80d418055 100644
--- a/nemo_aligner/data/nlp/builders.py
+++ b/nemo_aligner/data/nlp/builders.py
@@ -266,7 +266,7 @@ def build_dataset(index, name):
 build_train_valid_test_regression_rm_datasets = partial(build_train_valid_test_datasets, RegressionRewardModelDataset)
 
 
-def build_sft_dataset(data_cfg, tokenizer, num_samples, is_mamba, answer_only_loss=True, is_chat=True, special_tokens=None):
+def build_sft_dataset(data_cfg, tokenizer, num_samples, is_mamba=False, answer_only_loss=True, is_chat=True, special_tokens=None):
     packed_sequence = data_cfg.get("packed_sequence", False)
     dataset_kwargs = {}