Col of Concat-ed cell causes error when using Application.Index(arrS, i, 0) in diff Maro

I am using the Concatenation code I got (and modified into a function but I have not altered the code that concatinates) by @jindon, it works wonderfully.

The problem is that the column of concatenated cells throws a error in a different Macro that matches columns even though the concatinated column is not one of the matching columns of the matching macro.

If I delete the column of concatenated cells the matching Macro work fine.

The error ocrurs at this point in the matching macro

wsPB.Range("A" & j).Resize(1, sLC).Offset(1, pbOffset).Value = Application.Index(arrS, i, 0)

I am pretty sure the problem is

Application.Index(arrS, i, 0)

Is their a way to get the Concatenate code below to not produce this error when it encounters

Application.Index(arrS, i, 0)

Thank you

'Concatenate
'Sheet Name
'Delimeter
'Post Back Column
'Range
'Insert Column For Post Back Boolean

Sub Concat()

  ConCatX "XXX", "|", "B", "NewHeaderName", Range("B2,A2,D2,N2,L2"), True

End Sub

Function ConCatX(shtName As String, dilm As String, PBcol As String, NewHeaderName As String, Rng As Range, Optional pbInsertCol As Boolean = False)
Dim ws As Worksheet
Dim R As Range, i As Long
    
Set ws = ThisWorkbook.Sheets(shtName)

If pbInsertCol = True Then
    'Insert Column For Post Back
      ws.Columns(CLTCN(PBcol)).insert
      
ElseIf pbInsertCol = False Then

End If
    
   If Rng Is Nothing Then Exit Function
    With ws.Cells(1).CurrentRegion
        ReDim a(1 To .Rows.Count, 1 To 1)
        a(1, 1) = NewHeaderName
        For i = 2 To .Rows.Count
            For Each R In Rng
                If .Cells(i, R.Column) <> vbNullString Then
                    a(i, 1) = a(i, 1) & IIf(a(i, 1) = "", "", dilm) & .Cells(i, R.Column).Value
                End If
            Next
        Next
        
         With .Offset(, CLTCN(PBcol) - 1).Resize(, 1)
            .Value = a
        End With
    End With
End Function