diff --git a/ax/modelbridge/cross_validation.py b/ax/modelbridge/cross_validation.py
index e319e050650..e24c12050dd 100644
--- a/ax/modelbridge/cross_validation.py
+++ b/ax/modelbridge/cross_validation.py
@@ -566,12 +566,12 @@ def _predict_on_training_data(
     observations = observations_from_data(
         experiment=experiment, data=data
     )  # List[Observation]
-    observation_features = [obs.features for obs in observations]
 
-    # Transform observation features
-    observation_features = deepcopy(observation_features)
+    # Transform observations -- this will transform both obs data and features
     for t in model_bridge.transforms.values():
-        observation_features = t.transform_observation_features(observation_features)
+        observations = t.transform_observations(observations)
+
+    observation_features = [obs.features for obs in observations]
 
     # Make predictions in transformed space
     observation_data_pred = model_bridge._predict(observation_features)