I'm having an issue with TCP RST instead of FIN.

[pratik]

How about you try to use XAMPP and see if that behaves the same way? That way you can know that your problem is because of something at the phone end and not ESP8266 end.
Also, I would suggest stepping down to SDK v.2.0.0.
The latest version always ensures past issues are fixed, but initial releases are always prone to be buggy.
I cannot replicate the issue here because I do not have the phone and the setup you are using.

[pratik]

I suggested XAMPP because I wanted to rule out factors other than ESP8266 causing this issue.
But now that you have confirmed it is the firmware for sure, I will send this topic in to the SDK developers for feedback. It is a very specific issue, thanks for the detailed debug logs. I will get back to you soon.

[pratik]

If you could get the serial data up on a monitor or just attach some photos of the most relevant parts of the log, it would be great.
Do send me the wireshark logs on
pratik [at] espressif.com
I will patch the issue through to engineers. I do not have access to some confidential sources that drive the radio communication and so there is no way I can help directly with lower, networking level of issues.

[Her Mary]

Does the latest esp-at have the same issue? https://github.com/espressif/esp-at