VBA Code Not working when modified

Hello!

I have the following VBA Code on an Excel worksheet, which has been working fine up until today, when I modified it slightly (just changing Target.Offset(, 9) to Target.Offset(, 10), and it has now stopped working... Any idea why this might be please? I appreciate your help. Thanks!

Private Sub Worksheet_Change(ByVal Target As Range)
If Intersect(Target, Range("K2:K4000")) Is Nothing Then GoTo Next_Part
If Target.Count > 1 Then Exit Sub
If Target = "" Then
Target.Offset(, -8) = ""
Exit Sub
End If
With Application
.EnableEvents = False
.ScreenUpdating = False
Target.Offset(, -8) = Format(Date, "dd mmm yy")
.EnableEvents = True
.ScreenUpdating = True
End With

Next_Part:

If Intersect(Target, Range("L2:L4000")) Is Nothing Then GoTo Next_Part2
If Target.Count > 1 Then Exit Sub
If Target = "" Then
Target.Offset(, 9) = ""
Exit Sub
End If
With Application
.EnableEvents = False
.ScreenUpdating = False
Target.Offset(, 9).Value = Target.Offset(, 9).Value + 1
.EnableEvents = True
.ScreenUpdating = True
End With

Next_Part2:

If Intersect(Target, Range("L2:L4000")) Is Nothing Then GoTo Next_Part3
If Target.Count > 1 Then Exit Sub
If Target = "" Then
Target.Offset(, 10) = ""
Exit Sub
End If
With Application
.EnableEvents = False
.ScreenUpdating = False
Target.Offset(, 10).Value = Target.Offset(, 10).Value + 1
.EnableEvents = True
.ScreenUpdating = True
End With

Next_Part3:

If Intersect(Target, Range("L2:L4000")) Is Nothing Then GoTo Next_Part4
If Target.Count > 1 Then Exit Sub
If Target = "" Then
Target.Offset(, -6) = ""
Exit Sub
End If
With Application
.EnableEvents = False
.ScreenUpdating = False
Target.Offset(, -6) = Format(Date, "dd mmm yy")
.EnableEvents = True
.ScreenUpdating = True
End With


Next_Part4:

If Intersect(Target, Range("A2:A4000")) Is Nothing Then Exit Sub
If Target.Count > 1 Then Exit Sub
If Target = "" Then
Target.Offset(, 15) = ""
Exit Sub
End If
With Application
.EnableEvents = False
.ScreenUpdating = False
Target.Offset(, 15) = Format(Date, "dd mmm yy")
.EnableEvents = True
.ScreenUpdating = True
End With


End Sub