Exit Function doesn't break out of For loop?

Am writing a simple function to test of the existence of a worksheet in the current workbook

The code below evaluates to false each time even though WsName exists in the workbook wb.

Private Function WorkSheetExists(ByRef WsName As String, wb As Workbook) As Boolean
    
    Dim i As Long  
    
    For i = 1 to i= wb.Sheets.Count
        If (StrComp(WsName, wb.Sheets(i).Name) = 0) Then          
            WorkSheetExists = True
            Exit Function
        End If
        
       Next i

    WorkSheetExists = False
    
End Function

A little investigation reveals this is because the Exit Function statement isn't causing an exit of the Function.

My rewrite is:-

Private Function WorkSheetExists(ByRef WsName As String, wb As Workbook) As Boolean
    
    Dim i As Long
    Dim Found As Boolean
    
    Found = False
    i = 1
    
    Do While Not Found And i <= wb.Sheets.Count
        If (StrComp(WsName , wb.Sheets(i).Name) = 0) Then           
            Found = True
            WorkSheetExists = Found
'            Exit Function  'not needed as it doesn't exit function...but why?
        End If       
        
        i = i + 1
    Loop
    
    WorkSheetExists = Found
    
End Function

The rewrite works, just wondered why the Exit Function doesn't work in scenario 1?