diff --git a/openmc/cmfd.py b/openmc/cmfd.py
index 4e1fccb8be..c3df3f1047 100644
--- a/openmc/cmfd.py
+++ b/openmc/cmfd.py
@@ -368,7 +368,7 @@ class CMFD(object):
     @cmfd_mesh.setter
     def cmfd_mesh(self, mesh):
         check_type('CMFD mesh', mesh, CMFDMesh)
-        self._mesh = mesh
+        self._cmfd_mesh = mesh
 
     @norm.setter
     def norm(self, norm):
@@ -446,8 +446,8 @@ class CMFD(object):
             element.text = str(self._ktol)
 
     def _create_mesh_subelement(self):
-        if self._mesh is not None:
-            xml_element = self._mesh._get_xml_element()
+        if self._cmfd_mesh is not None:
+            xml_element = self._cmfd_mesh._get_xml_element()
             self._cmfd_file.append(xml_element)
 
     def _create_norm_subelement(self):
diff --git a/openmc/summary.py b/openmc/summary.py
index 37509ec373..b283ed502c 100644
--- a/openmc/summary.py
+++ b/openmc/summary.py
@@ -387,7 +387,7 @@ class Summary(object):
 
                 # Set the distribcell offsets for the lattice
                 if offsets is not None:
-                    lattice.offsets = offsets[:, ::-1, :]
+                    lattice.offsets = offsets
 
                 # Add the Lattice to the global dictionary of all Lattices
                 self.lattices[index] = lattice
diff --git a/openmc/tallies.py b/openmc/tallies.py
index d5d6df03fd..d592377186 100644
--- a/openmc/tallies.py
+++ b/openmc/tallies.py
@@ -1327,7 +1327,7 @@ class Tally(object):
 
                     # Create list of cell instance IDs for distribcell Filters
                     elif isinstance(self_filter, openmc.DistribcellFilter):
-                        bins = np.arange(self_filter.num_bins)
+                        bins = [i for i in range(self_filter.num_bins)]
 
                     # Create list of IDs for bins for all other filter types
                     else:
@@ -2258,12 +2258,12 @@ class Tally(object):
         # Construct lists of tuples for the bins in each of the two filters
         filters = [type(filter1), type(filter2)]
         if isinstance(filter1, openmc.DistribcellFilter):
-            filter1_bins = np.arange(filter1.num_bins)
+            filter1_bins = [i for i in range(filter1.num_bins)]
         else:
             filter1_bins = [filter1.get_bin(i) for i in range(filter1.num_bins)]
 
         if isinstance(filter2, openmc.DistribcellFilter):
-            filter2_bins = np.arange(filter2.num_bins)
+            filter2_bins = [i for i in range(filter2.num_bins)]
         else:
             filter2_bins = [filter2.get_bin(i) for i in range(filter2.num_bins)]
 
@@ -3257,8 +3257,8 @@ class Tally(object):
                 if isinstance(self_filter, filter_type):
                     mean = np.take(mean, indices=bin_indices, axis=i)
                     std_dev = np.take(std_dev, indices=bin_indices, axis=i)
-                    mean = np.mean(mean, axis=i, keepdims=True)
-                    std_dev = np.mean(std_dev**2, axis=i, keepdims=True)
+                    mean = np.nanmean(mean, axis=i, keepdims=True)
+                    std_dev = np.nanmean(std_dev**2, axis=i, keepdims=True)
                     std_dev /= len(bin_indices)
                     std_dev = np.sqrt(std_dev)
 
@@ -3282,8 +3282,8 @@ class Tally(object):
             axis_index = self.num_filters
             mean = np.take(mean, indices=nuclide_bins, axis=axis_index)
             std_dev = np.take(std_dev, indices=nuclide_bins, axis=axis_index)
-            mean = np.mean(mean, axis=axis_index, keepdims=True)
-            std_dev = np.mean(std_dev**2, axis=axis_index, keepdims=True)
+            mean = np.nanmean(mean, axis=axis_index, keepdims=True)
+            std_dev = np.nanmean(std_dev**2, axis=axis_index, keepdims=True)
             std_dev /= len(nuclide_bins)
             std_dev = np.sqrt(std_dev)
 
@@ -3301,8 +3301,8 @@ class Tally(object):
             axis_index = self.num_filters + 1
             mean = np.take(mean, indices=score_bins, axis=axis_index)
             std_dev = np.take(std_dev, indices=score_bins, axis=axis_index)
-            mean = np.sum(mean, axis=axis_index, keepdims=True)
-            std_dev = np.sum(std_dev**2, axis=axis_index, keepdims=True)
+            mean = np.nanmean(mean, axis=axis_index, keepdims=True)
+            std_dev = np.nanmean(std_dev**2, axis=axis_index, keepdims=True)
             std_dev /= len(score_bins)
             std_dev = np.sqrt(std_dev)
 
diff --git a/tests/test_asymmetric_lattice/results_true.dat b/tests/test_asymmetric_lattice/results_true.dat
index dda6f953f9..34c8faa64d 100644
--- a/tests/test_asymmetric_lattice/results_true.dat
+++ b/tests/test_asymmetric_lattice/results_true.dat
@@ -1 +1 @@
-e18c2318bab6c42a263e5079fd796b1bee609e4274884fbc7bfd8b33e59aeb5e5a167da8e093f339f766815e007bd606c002939e3f730af523cbc9cf75c53faa
\ No newline at end of file
+b70886031e22db9e3f0332eac703a7356504750c1e90d7083ffd16b8884d00661d0e20c6d8bead3c93369b2e7c105ca3280c7858ca6a147fa6669a5d3d530461
\ No newline at end of file