diff --git a/alf/algorithms/algorithm.py b/alf/algorithms/algorithm.py
index 19a6db97b..0fae27277 100644
--- a/alf/algorithms/algorithm.py
+++ b/alf/algorithms/algorithm.py
@@ -29,7 +29,7 @@
 from torch.nn.modules.module import _IncompatibleKeys, _addindent
 
 import alf
-from alf.data_structures import AlgStep, LossInfo, StepType, TimeStep
+from alf.data_structures import AlgStep, LossInfo, StepType, TimeStep, BasicRolloutInfo
 from alf.experience_replayers.replay_buffer import BatchInfo, ReplayBuffer
 from alf.optimizers.utils import GradientNoiseScaleEstimator
 from alf.utils.checkpoint_utils import (is_checkpoint_enabled,
@@ -1368,6 +1368,13 @@ def train_step_offline(self, inputs, state, rollout_info, pre_train=False):
               customized training.
         """
         try:
+            if isinstance(rollout_info, BasicRolloutInfo):
+                logging.log_first_n(
+                    logging.WARNING,
+                    "Detected offline buffer training without Agent wrapper. "
+                    "For best compatibility, it is advised to use the Agent wrapper.",
+                    n=1)
+                rollout_info = rollout_info.rl
             return self.train_step(inputs, state, rollout_info)
         except:
             # the default train_step is not compatible with the
diff --git a/alf/algorithms/sac_algorithm.py b/alf/algorithms/sac_algorithm.py
index f2363bd41..5044ba3e9 100644
--- a/alf/algorithms/sac_algorithm.py
+++ b/alf/algorithms/sac_algorithm.py
@@ -27,13 +27,12 @@
 from alf.algorithms.config import TrainerConfig
 from alf.algorithms.off_policy_algorithm import OffPolicyAlgorithm
 from alf.algorithms.one_step_loss import OneStepTDLoss
-from alf.algorithms.rl_algorithm import RLAlgorithm
-from alf.data_structures import TimeStep, Experience, LossInfo, namedtuple
+from alf.data_structures import TimeStep, LossInfo, namedtuple
 from alf.data_structures import AlgStep, StepType
 from alf.nest import nest
 import alf.nest.utils as nest_utils
 from alf.networks import ActorDistributionNetwork, CriticNetwork
-from alf.networks import QNetwork, QRNNNetwork
+from alf.networks import QNetwork
 from alf.tensor_specs import TensorSpec, BoundedTensorSpec
 from alf.utils import losses, common, dist_utils, math_ops
 from alf.utils.normalizers import ScalarAdaptiveNormalizer
@@ -847,6 +846,7 @@ def _select_q_value(self, action, q_values):
     def _critic_train_step(self, observation, target_observation,
                            state: SacCriticState, rollout_info: SacInfo,
                            action, action_distribution):
+
         critics, critics_state = self._compute_critics(
             self._critic_networks,
             observation,