Calendar not forwarding more than 1 month

[cokelopez]

I tried to use the code for a calendar in my python bot the following way:

def get_telefono(update: Update, context: CallbackContext) -> None:
    telefono = update.message.text
    context.user_data['telefono'] = telefono
    user_data = context.user_data
    respuesta = 'Fecha de Vencimiento AAAA-MM-DD'
    calendar = telegramcalendar.create_calendar()
    update.message.reply_text(respuesta, reply_markup=calendar)
    return GET_VENCIMIENTO

def get_vencimiento(update: Update, context: CallbackContext) -> None:
    bot = context.bot
    selected, date = telegramcalendar.process_calendar_selection(bot, update)
   
    if selected:
        respuesta = date.strftime("%d/%m/%Y")
        update.message.reply_text(respuesta, reply_markup=ReplyKeyboardRemove())
    return GET_PAGO

updater = Updater(settings.TOKEN)
        dispatcher = updater.dispatcher

        conv_handler = ConversationHandler(
            entry_points=[CommandHandler('start', start, Filters.user(username="@cokelopez"))],
            states={

            
                GET_TELEFONO: [MessageHandler(Filters.regex('^\+?1?\d{9,15}$'), get_telefono)],
                GET_VENCIMIENTO: [CallbackQueryHandler(get_vencimiento)],
            
                
            },
            fallbacks=[CommandHandler('cancel', cancel)],
            allow_reentry = True,

        )
        dispatcher.add_handler(conv_handler)
        dispatcher.add_error_handler(error)

        mode = os.environ.get("MODE", "polling")
      
        updater.start_polling()

        updater.idle()

The calendar is displayed and it start in August 2021 I click to forward to September and it workd, but when I try to forward to October or go back to August it does not work.

I'm using Django as a framework, I just pasted part of the code of my bot, I'm using the Context because I collect the answers.