diff --git a/include/openmc/cell.h b/include/openmc/cell.h
index fd1883ce57..8171967273 100644
--- a/include/openmc/cell.h
+++ b/include/openmc/cell.h
@@ -244,7 +244,7 @@ protected:
   bool contains_simple(Position r, Direction u, int32_t on_surface) const;
   bool contains_complex(Position r, Direction u, int32_t on_surface) const;
   BoundingBox bounding_box_simple() const;
-  static BoundingBox bounding_box_complex(vector<int32_t> rpn);
+  static BoundingBox bounding_box_complex(vector<int32_t> postfix);
 
   //! Applies DeMorgan's laws to a section of the RPN
   //! \param start Starting point for token modification
diff --git a/src/cell.cpp b/src/cell.cpp
index 4a61eb60e2..5c3e06eef3 100644
--- a/src/cell.cpp
+++ b/src/cell.cpp
@@ -624,6 +624,7 @@ CSGCell::CSGCell(pugi::xml_node cell_node)
     for (auto it = region_.begin(); it != region_.end(); it++) {
       if (*it == OP_INTERSECTION || *it > OP_COMPLEMENT) {
         region_.erase(it);
+        it--;
       }
     }
     region_.shrink_to_fit();
@@ -807,7 +808,7 @@ void CSGCell::remove_complement_ops(vector<int32_t>& infix)
     // positions in the RPN
     apply_demorgan(it, stop);
     // update iterator position
-    it = std::find(it, infix.end(), OP_COMPLEMENT);
+    it = std::find(infix.begin(), infix.end(), OP_COMPLEMENT);
   }
 }