a problem with chunked encoding (no replies)

I wrote a php script, for socks over http proxy, generating “chunked encoding” format, adding a header(Transfer-Encoding: chunked)
and I first used apache, it works well.
But when I used nginx/php-fpm, I found the response chunked encoding twice.

I tried to turn off chunked encoding with "chunked_transfer_encoding off", but in the response header, there were no "Transfer-Encoding: chunked"
that i added in the php script.

How to solve the problem. Sorry about my broken English.

Here is my script:
https://github.com/esxgx/highway/blob/master/tun-crypt.php