Non zero electronic current at the electrode separator interface

[vermaprk]

Hello
I am trying to build a lithium sulfur model on pybamm similar to the DFN except the pseudo 2D solid state diffusion. However, in the current model I am getting errors in electronic current values at the anode-separator and anode-cathode interface. The plot for electronic current in the electrodes and ionic current in the electrolyte is attached. The electronic current at the separator interface should always be 0 and the ionic current should be equal to the applied current. This is implied by the Neumann boundary condition grad phi_s =0 at both the interfaces as given below:
Left region is anode; separator is mid; and cathode is right

self.boundary_conditions = {
           phi_sa: {
               "left": (pybamm.Scalar(0), "Dirichlet"),
               "right": (pybamm.Scalar(0), "Neumann"),
           },phi_sc: {
               "left": (pybamm.Scalar(0), "Neumann"),
               "right": (-I_app / sigma, "Neumann"),
           },
           phi_l: {
               "left": (pybamm.Scalar(0), "Neumann"),
               "right": (pybamm.Scalar(0), "Neumann"),
           },
           c_Li: {
               "left": (-I_app/(F*D_Li), "Neumann"),
               "right": (pybamm.Scalar(0), "Neumann")},
}

But my electronic current at the both separator interface is non-zero. I have also plotted the expression sum of ionic and electronic current subtracted by the applied current. This expression should be 0 but is non-zero at the interface. Surprisingly, for electrolyte current these values are correct as ionic ionic current = applied current at the both separator interfaces.

Upon few discussion with pybamm peers I came to know that there is some error related to the boundary condition execution as b.c are defined at the nodes and are extrapolated at the edges of a control volume (something I have no idea about). Please look into the issue.

Thanks