tkinter button press sometimes block thread execution

Question

I have a button in tkinter that execute a function in a loop while the button is pressed like this:

self.APRTE_button = tk.Button(self, text="Button", width=20, height=2,
                              command=lambda: self.button_hold_callback('APRTE'))
self.APRTE_button.bind('<Button-1>',
                       lambda event: self.button_hold_callback('APRTE', event))
self.APRTE_button.bind('<ButtonRelease-1>', self.button_stop_callback)

The two functions are

def button_hold_callback(self, *args):
    global repeat
    self.ser_send_text.delete('1.0', tk.END)

    try:
        repeat = self.after(450, self.button_hold_callback, args[0], args[1])
    except IndexError:
        pass

    self.ser.write(DATA_TO_WRITE)


def button_stop_callback(self, event):
    self.ser.reset_output_buffer()
    self.ser.write(b'\x02\x56\xff\xff\xff\xff\xff\xff\x32\x35\x04')
    logging.info("Written stop on the serial")
    self.ser.close()
    self.after_cancel(repeat)

I'm using a tkinter with a modified loop as below

def mainloop(self):
    with ThreadPoolExecutor() as executor:
        future = executor.submit(self._do_update_screen_loop)
        try:
            return super().mainloop()
        finally:
            # letting the thread know we're done
            self._terminating.set()
            with self._update_scheduled:
                self._update_scheduled.notify_all()

def update_screen(self):
    with self._update_scheduled:
        self._update_scheduled.notify_all()
    self.after(110, self.update_screen)

def _do_update_screen_loop(self):
    while True:
        with self._update_scheduled:
            self._update_scheduled.wait()
        if self._terminating.is_set():
            return
        self._do_data_screen()

if __name__ == "__main__":
    app = SampleApp()
    app.mainloop()

For some reason, when I kept clicked the button for long time or repetitive click it a lot of time, the _do_data_screen() function, which the only thing to do is listening to the serial port, basically stop executing. I know it because I know data are coming on the serial but the doesn't print something