diff --git a/lmfdb/genus2_curves/web_g2c.py b/lmfdb/genus2_curves/web_g2c.py
index f223f57bd7..d84496ac06 100644
--- a/lmfdb/genus2_curves/web_g2c.py
+++ b/lmfdb/genus2_curves/web_g2c.py
@@ -984,7 +984,7 @@ def make_object(self, curve, endo, tama, ratpts, clus, galrep, nonsurj, is_curve
             data['split_statement'] = split_statement(data['split_coeffs'], data.get('split_labels'), data['split_condnorms'])
 
         # Nonsurjective primes data
-        if not nonsurj:
+        if nonsurj is None:
             data['exists_nonsurj_data'] = False
         else:
             data['exists_nonsurj_data'] = True