diff --git a/openmc/mgxs/mgxs.py b/openmc/mgxs/mgxs.py
index d7a17201af..3471671e84 100644
--- a/openmc/mgxs/mgxs.py
+++ b/openmc/mgxs/mgxs.py
@@ -3869,7 +3869,7 @@ class ScatterMatrixXS(MatrixMGXS):
 
             # Add filters for transport correction
             if self.correction == 'P0' and self.legendre_order == 0:
-                filters.append([[energyout]])
+                filters.append([energyout])
 
         return self._add_angle_filters(filters)