excel "insert line" causing error with target.offset

I have this simple bit of code that automates some dates and stuff when adding line items to a sheet. It works well, but when I insert a line in to the spreadsheet [right-click the line name > insert] an error occurs.

Private Sub Worksheet_Change(ByVal Target As Range)
    Dim cell As Range
    Dim plusWeek
    plusWeek = Now() + 7

For Each cell In Target
    '========adds closed date, deleted date if status degenerates=========
    If cell.Column = 13 And cell = "Closed" Then
        Target.Offset(0, -2) = Format(Now(), "yyyy-mm-dd")
    End If
    If cell.Column = 13 And cell = "In-Progress" Then
        Target.Offset(0, -2) = ""
    End If
    If cell.Column = 13 And cell = "Open" Then
        Target.Offset(0, -2) = ""
    End If

    '========adds date added if date is embty and description is not empty========
    If cell.Column = 8 And IsEmpty(Target.Offset(0, 1)) And Not IsEmpty(Target.Offset(0, 0)) Then
        Target.Offset(0, 1) = Format(Now(), "yyyy-mm-dd")
        Target.Offset(0, 2) = Format(plusWeek, "yyyy-mm-dd")
        Target.Offset(0, 5) = "Open"
    End If
    '========deletes date added if description is empty========
    'If cell.Column = 8 And IsEmpty(Target.Offset(0, 0)) Then
    '    Target.Offset(0, 1) = ""'End If

Next cell
End Sub

if I paste a line, add a line or delete a line, error 1004 occurs. The debugger highlights this line, but I can't understand where the error comes from.

 If cell.Column = 8 And IsEmpty(Target.Offset(0, 1)) And Not 
 IsEmpty(Target.Offset(0, 0)) Then