Forces from surfacesClose dont add up

Hello Team, greetings. I'm trying to account for the van der waals forces in my simulation. In order to that

1. I first started with copy-pasting and editing the existing cohesion model and very soon found that ".is_wall" in surfacesClose( ) is always false. That means, it does not detect the presence of walls. There is also a post on this and its implementation is in progress.

2. I then edited the normal_model_hooke.h and added vdw component to the surfacesIntersect and surfacesClose functions. The math is correct, vdw forces are written out to terminal for both these functions (using cout statements). But when I post-process the case, the force contribution from surfacesClose is always zero even when there is a non-zero vdw force. I can see force contribution from surfacesIntersect function though.

Originally surfacesClose is as shown below.
void surfacesClose(SurfacesCloseData &scdata, ForceData&, ForceData&)
{
if (scdata.contact_flags)
*scdata.contact_flags |= CONTACT_NORMAL_MODEL;
dissipateElasticPotential(scdata);
}

and now I add the vdw force to this as

void surfacesClose(SurfacesCloseData &scdata, ForceData & i_forces, ForceData & j_forces)
{
if (scdata.contact_flags)
*scdata.contact_flags |= CONTACT_NORMAL_MODEL;
dissipateElasticPotential(scdata);
// All code related to vdw force
//i_forces and j_forces if else lines
}

What could have gone wrong in this?

Thank you,
Jagan Mohan.