diff --git a/extensions/chaeo/examples/transfer_labels_to_ilastik_object_classifier.py b/extensions/chaeo/examples/transfer_labels_to_ilastik_object_classifier.py
index 5608417fdd3ad8549fb0f4db81e1d79fa7ce8700..6dd5e27d59e98f6a3ee0ddd2a37c50261236c404 100644
--- a/extensions/chaeo/examples/transfer_labels_to_ilastik_object_classifier.py
+++ b/extensions/chaeo/examples/transfer_labels_to_ilastik_object_classifier.py
@@ -198,7 +198,7 @@ def compare_object_maps(truth: GenericImageDataAccessor, inferred: GenericImageD
             ob_id = skimage.measure.label(inf_img)
             pr = skimage.measure.regionprops_table(ob_id, properties=['label', 'area'])
             mask = inf_img == pr['label'][pr['area'].argmax()]
-            dd['inferred_label'] = np.unique(mask * inf_img)[1]
+            dd['inferred_label'] = np.unique(mask * inf_img)[-1]  # occasionally no object in frame
             dd['multiples'] = True
         else:  # exactly one unique object class in frame
             dd['inferred_label'] = unique[1]