here is with the body filter disabled (works normally):

HTTP/1.1 200 OK
Server: nginx/1.12.0
Date: Thu, 11 Jan 2018 04:16:07 GMT
Content-Type: text/html
Transfer-Encoding: chunked
Connection: keep-alive

here is with the body filter enabled (connection does not terminate):

HTTP/1.1 200 OK
Server: nginx/1.12.0
Date: Thu, 11 Jan 2018 04:19:59 GMT
Content-Type: text/html
Transfer-Encoding: chunked
Connection: keep-alive

Essentially the same.