diff --git a/brainscore_vision/model_helpers/brain_transformation/behavior.py b/brainscore_vision/model_helpers/brain_transformation/behavior.py
index 28aeb9e6a..97cc62dcd 100644
--- a/brainscore_vision/model_helpers/brain_transformation/behavior.py
+++ b/brainscore_vision/model_helpers/brain_transformation/behavior.py
@@ -192,7 +192,7 @@ def start_task(self, task: BrainModel.Task, fitting_stimuli, number_of_trials=1,
                                                   number_of_trials=number_of_trials,
                                                   require_variance=require_variance)
         fitting_features = fitting_features.transpose('presentation', 'neuroid')
-        assert all(fitting_features['stimulus_id'].values == fitting_stimuli['stimulus_id'].values), \
+        assert all(self.order_preserving_unique(fitting_features['stimulus_id'].values) == fitting_stimuli['stimulus_id'].values), \
             "stimulus_id ordering is incorrect"
         self.classifier.fit(fitting_features, fitting_features['image_label'])
 
@@ -241,6 +241,16 @@ def labels_to_indices(self, labels):
             index2label = OrderedDict((index, label) for label, index in label2index.items())
             return indices, index2label
 
+    @staticmethod
+    def order_preserving_unique(array):
+        """
+        This function sorts an array and removes duplicates while preserving the order of the elements.
+        This function is used in favor of np.unique to ensure that the order of the stimulus_ids is preserved, as
+        np.unique performs sorting on the array.
+        """
+        _, indices = np.unique(array, return_index=True)
+        return array[np.sort(indices)]
+
 
 class OddOneOut(BrainModel):
     def __init__(self, identifier: str, activations_model, layer: Union[str, List[str]]):