Sub_filter can't work with gzip

now i use Centos5.2/nginx-0.8.41/php5.2.13,
–with-http_stub_status_module --with-http_ssl_module
–with-http_sub_module
but I found HttpSubModule/sub_filter can’t work when gzip open.
a bug? thank you

Posted at Nginx Forum:
http://forum.nginx.org/read.php?2,100183,100183#msg-100183