Spanish File.ReadString funciona a veces

Sub Buscar_lista_de_paises
    
    Dim req As OkHttpRequest
    Dim Query As String
    Query="SELECT nombre, ID FROM paises ORDER BY ID"
    req.InitializePost2("http://192.168.0.14/paises.php", Query.GetBytes("UTF8"))
    hc.Execute(req, paises) '''''''' En ResponseSuccess hará el Case de paises
    
End Sub

Sub hc_ResponseSuccess (Response As OkHttpResponse, tarea As Int)
    Dim res As String

    File.Delete(File.DirDefaultExternal,"respuesta.csv")
    Response.GetAsynchronously("Nombre_del_evento",File.OpenOutput(File.DirDefaultExternal,"respuesta.csv",True),True,1)   
    res=File.ReadString(File.DirDefaultExternal, "respuesta.csv")
    Log("Respuesta= :"&res)

End Sub

Sub hc_ResponseSuccess (Response As OkHttpResponse, tarea As Int)
  File.Delete(File.DirDefaultExternal,"respuesta.csv")
Response.GetAsynchronously("FileResponse",File.OpenOutput(File.DirDefaultExternal,"respuesta.csv",True),True,1)  
  
End Sub

Sub FileResponse_StreamFinish (Success As Boolean, TaskId As Int)
  If Success = False Then
    Log("error")
    Return
  End If
 
Dim res as String=File.ReadString(File.DirDefaultExternal, "respuesta.csv")
Log("Respuesta= :"&res)
End Sub