How to send and receive text data using Bluetooth in my Flutterflow project

I am trying to make a Bluetooth connection using my device and this tutorial. But it is not working on my device, I have configured it correctly following the guide.

guide code

However, on the homepage, there is a duplicate list of devices in the connected devices list and the scanned devices list. This happens when I reopen the app.

And the next problem is that I am not receiving data from other devices. I can send messages to other devices. I just can't receive them.
Why is this happening and how can I fix it? I am currently using flutter_blue_plus: 1.8.4. This version works better than other versions.

This is my project cloned from the guide.

my code

I have tried with this guide. flutter_blue_plus: 1.8.4

But still repeating and not receiving problem exist.

I'll show you my screen results.

scanned device list
sending message
connected device list
repeated connected device list

Please give me advice, it is very thanks for me!