Web servers can return data in various formats to be identified with Transfer-Encoding header. The ProxySG supports the headers outlined in HTTP/1.1 RFC 2616, but if an unknown type Transfer-Encoding header is returned from the server or if the server returns the "identity" encoding, the ProxySG returns the data to the client as "chunked" encoding, without identifying as being "chunked" encoding. 

RFC 2616 says regarding "identity" for content encoding:

  The default (identity) encoding; the use of no transformation whatsoever. This
  content-coding is used only in the Accept- Encoding header, and SHOULD NOT be
  used in the Content-Encoding header.
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Regardless of the RFC, the proxy should ignore the Transfer-Encoding "identity" header and any
other unmentioned/unsupported headers being returned from the origin server.

This is a bug in SGOS.

This bug is addressed in SGOS 6.5.5.5 and later releases.

Workaround

HTTP/1.0 did not support chunked encoding. To work around this issue, downgrade the
HTTP responses to clients  HTTP/1.0 using policy.

For example, if site abc.com is exhibiting this issue, then to work-around it you would use
the policy in the local policy file:

<Proxy>
url.domain=abc.com http.response.version(1.0)