AJAX truncated response on Phusion Passenger v3.0.17 on CentOS v6.x

Our application deployed on Phusion Passenger version 3.0.17 server on
CentOS 6.x box makes a AJAX call which returns a large response ranging
from 1MBs to 8 MBs. It works fine a lot of time but we have seen
response from the server inconsistently. Its breaks are different places
for the same response and is not because of escape characters. The
doesn’t break or show any error logs. It returns a 200 OK HTTP status
the truncated request also.

We are running the Phusion Passenger server in standalone mode without
nginx or apache fronting. Whats could be the issue?