"zero size buf in output" flooding the error.log

I am using the external NGiNX_HTTP_Push_Module, and whenever a
response is issued by one of its channels, I get this error logged:

2011/10/12 19:33:30 [alert] 10808#0: *64 zero size buf in output t:1
r:0 f:0 0000000001240C98 0000000001240C98-0000000001240C98
0000000000000000 0-0, client:, server: localhost, request:
“GET /event?id=hJsrnGIdbngARLNBiNMoIO HTTP/1.1”, host: “XXXXXXXXXXX”,

Those ‘client’ and ‘server’ fields are strange, because they always
point to localhost, even if connection is external.

By “greping” through the source I found the message is logged by
ngx_output_chain.c:100, where I saw that this is clearly a debug
message, because of all the pointers it prints. So I thought it might
be a bug on the NGiNX_HTTP_Push_Module that triggers the situation.
What might be the issue on the module? What can trigger this message?

Lucas Clemente Vella
[email protected]