Merge cells doesn't work after locking and unlocking other cell - excel

Question

I've got a sheet in which I'm trying to merge some cells based on CX cell value. CX cell is also dynamically locked/unlocked based on BX cell value. Although locking/unlocking works fine, I get 1004 error when I'm trying to merge cells with line:
Range(Cells(Target.Row, i), Cells(Target.Row + Target.Value - 1, i)).Merge
While code is below.
Option Explicit
Private Sub Workbook_SheetChange(ByVal Sh As Object, ByVal Target As Range)
If Not Intersect(Target, Range("B14:B50")) Is Nothing And Sh.Name <> "Dane" Then
Dim pass As String
pass = "" 'set the password. Otherwise, protection/unprotection is done without a pass
If Target.Cells.Count > 1 Then Exit Sub
ActiveSheet.Unprotect pass
If Target.Value = "Unlocked" Then
Target.Offset(0, 1).Locked = False
Else
Target.Offset(0, 1).Value = 0
Target.Offset(0, 1).Locked = True
End If
ActiveSheet.Protect pass
End If
If Not Intersect(Target, Range("C14:C50")) Is Nothing And Sh.Name <> "Dane" Then
Dim i As Long
Application.DisplayAlerts = False
For i = 1 To 8 Step 1
If i <> 6 And i <> 7 And Cells(Target.Row, i).MergeCells Then
Cells(Target.Row, i).UnMerge
End If
Next i
If Target.Value <> 0 Then
For i = 1 To 8 Step 1
If i <> 6 And i <> 7 Then
Range(Cells(Target.Row, i), Cells(Target.Row + Target.Value - 1, i)).Merge
End If
Next i
End If
Application.DisplayAlerts = True
End If
End Sub

Answer 1

Okay. So with #FaneDuru comments, I've been able to figure out the issue. Sheet protection was causing the problem, so I had to unprotect and reprotect sheet before for loops in second condition. Also, #FaneDuru advised to set EnableEvents = false there, to prevent any infinite loop issue. Below is the fixed code.
Option Explicit
Private Sub Workbook_SheetChange(ByVal Sh As Object, ByVal Target As Range)
If Not Intersect(Target, Range("B14:B50")) Is Nothing And Sh.Name <> "Dane" Then
Dim pass As String
pass = "" 'set the password. Otherwise, protection/unprotection is done without a pass
If Target.Cells.Count > 1 Then Exit Sub
ActiveSheet.Unprotect pass
If Target.Value = "Unlocked" Then
Target.Offset(0, 1).Locked = False
Else
Target.Offset(0, 1).Value = 0
Target.Offset(0, 1).Locked = True
End If
ActiveSheet.Protect pass
End If
If Not Intersect(Target, Range("C14:C50")) Is Nothing And Sh.Name <> "Dane" Then
Dim i As Long
Application.DisplayAlerts = False
Application.EnableEvents = False
ActiveSheet.Unprotect pass
For i = 1 To 8 Step 1
If i <> 6 And i <> 7 And Cells(Target.Row, i).MergeCells Then
Cells(Target.Row, i).UnMerge
End If
Next i
If Target.Value <> 0 Then
For i = 1 To 8 Step 1
If i <> 6 And i <> 7 Then
Range(Cells(Target.Row, i), Cells(Target.Row + Target.Value - 1, i)).Merge
End If
Next i
End If
ActiveSheet.Protect pass
Application.EnableEvents = True
Application.DisplayAlerts = True
End If
End Sub
However, I'm still wondering why I need to unprotect the sheet to edit unlocked range.