diff --git a/dumux/discretization/staggered/globalfacevariables.hh b/dumux/discretization/staggered/globalfacevariables.hh
index 58a892ad21fefc782c8d8f2be92a01a0a77312d7..6e4ff413782ba5d94b3e978b3098b63b3ea0680b 100644
--- a/dumux/discretization/staggered/globalfacevariables.hh
+++ b/dumux/discretization/staggered/globalfacevariables.hh
@@ -81,7 +81,7 @@ public:
         problemPtr_ = &problem;
 
         faceVariables_.resize(problem.model().numFaceDofs());
-        assert(faceVariables_.size == sol.size());
+        assert(faceVariables_.size() == sol.size());
 
         for(int i = 0; i < problem.model().numFaceDofs(); ++i)
         {
diff --git a/dumux/discretization/staggered/staggeredgeometryhelper.hh b/dumux/discretization/staggered/staggeredgeometryhelper.hh
index 0eb8233df9d56bc1908607e90677001b4e14917d..70e52a9730872d02c979d37d4d08a78627439498 100644
--- a/dumux/discretization/staggered/staggeredgeometryhelper.hh
+++ b/dumux/discretization/staggered/staggeredgeometryhelper.hh
@@ -110,8 +110,8 @@ public:
     Scalar selfToOppositeDistance() const
     {
         const auto inIdx = intersection_.indexInInside();
-        const auto& self = element_.template subEntity <1> (inIdx);
-        const auto& opposite = element_.template subEntity <1> (localOppositeIdx_(inIdx));
+        const auto self = element_.template subEntity <1> (inIdx);
+        const auto opposite = element_.template subEntity <1> (localOppositeIdx_(inIdx));
         return (self.geometry().center() - opposite.geometry().center()).two_norm();
     }
 
@@ -308,9 +308,10 @@ protected:
         return this->gridView_.indexSet().subIndex(element, localIdx, codimCommonEntity);
     };
 
-    const Intersection& intersection_; //! The intersection of interest
-    const Element& element_; //! The respective element
-    const typename Element::Geometry& elementGeometry_; //! Reference to the element geometry
+    // TODO: check whether to use references here or not
+    const Intersection intersection_; //! The intersection of interest
+    const Element element_; //! The respective element
+    const typename Element::Geometry elementGeometry_; //! Reference to the element geometry
     const GridView gridView_;
     const int offset_; //! Offset for intersection dof indexing
     std::array<PairData<Scalar, GlobalPosition>, numPairs> pairData_; //! collection of pair information
diff --git a/dumux/freeflow/staggered/indices.hh b/dumux/freeflow/staggered/indices.hh
index 11ce35e9b8e8fcbed744e01b89d33a61d2cbbbad..636a58d6d285f9ba9b10f74bfc224700597e9299 100644
--- a/dumux/freeflow/staggered/indices.hh
+++ b/dumux/freeflow/staggered/indices.hh
@@ -50,7 +50,7 @@ struct NavierStokesCommonIndices
     static const int dimYIdx = 1; //!< Index of the y-component of a vector of size dim
     static const int dimZIdx = 2; //!< Index of the z-component of a vector of size dim
 
-    static const int massBalanceIdx = dim; //!< Index of the mass balance equation
+    static const int massBalanceIdx = PVOffset + 0; //!< Index of the mass balance equation
     static const int conti0EqIdx = massBalanceIdx; //!< Index of first (for C-guys: 0th) mass conservation equation
 
     static const int pressureIdx = massBalanceIdx; //!< Index of the pressure in a solution vector