Can you test this mod and see what it does:
else
{
InputPS->SetBeamSourcePoint(0, InSplinePoints*, i);
InputPS->SetBeamTargetPoint(0, InSplinePoints[i + 1], i);
/* Tangent Towards The Next Point In The Spline */
FVector LeaveTangent = FVector(InSplinePoints[i - 1] - InSplinePoints[i + 1]);
LeaveTangent.Normalize();
FVector EnterTangent = FVector(InSplinePoints[i - 1+1] - InSplinePoints[i + 1+1]);
EnterTangent.Normalize();
**InputPS->SetBeamSourceTangent(0, -LeaveTangent, i);
InputPS->SetBeamTargetTangent(0, EnterTangent , i);
**}