diff --git a/src/lerobot/processor/batch_processor.py b/src/lerobot/processor/batch_processor.py
index 1ba016b4e..a563599cd 100644
--- a/src/lerobot/processor/batch_processor.py
+++ b/src/lerobot/processor/batch_processor.py
@@ -34,6 +34,7 @@ from .pipeline import (
     PolicyActionProcessorStep,
     ProcessorStep,
     ProcessorStepRegistry,
+    TransitionKey,
 )
 
 
@@ -227,9 +228,12 @@ class AddBatchDimensionProcessorStep(ProcessorStep):
         Returns:
             The environment transition with a batch dimension added.
         """
-        transition = self.to_batch_action_processor(transition)
-        transition = self.to_batch_observation_processor(transition)
-        transition = self.to_batch_complementary_data_processor(transition)
+        if transition[TransitionKey.ACTION] is not None:
+            transition = self.to_batch_action_processor(transition)
+        if transition[TransitionKey.OBSERVATION] is not None:
+            transition = self.to_batch_observation_processor(transition)
+        if transition[TransitionKey.COMPLEMENTARY_DATA] is not None:
+            transition = self.to_batch_complementary_data_processor(transition)
         return transition
 
     def transform_features(