diff --git a/pygsti/models/model.py b/pygsti/models/model.py
index 8622f7d50..b5298c98d 100644
--- a/pygsti/models/model.py
+++ b/pygsti/models/model.py
@@ -1311,7 +1311,7 @@ def split_circuits(self, circuits, erroron=('prep', 'povm'), split_prep=True, sp
                     else: 
                         povm_lbl = None
                         circuit = ckt
-            split_circuits.append((None, circuit, povm_lbl))
+                split_circuits.append((None, circuit, povm_lbl))
         
         else:
             split_circuits = [(None, ckt, None) for ckt in circuits]