ZF-11263: Zend_Http_Respons fails to gzinflate some server responses
Imported http://rss1.smashingmagazine.com/feed/] with Zend_Feed_Reader was giving my gzinflate "data error" warnings. Managed to trace it back to Zend_Http_Response::decodeGzip() not checking for additional headers in the gzipped data it was being passed.
The PEAR HTTP_Request package encountered a [similar bug in 2006 and the fixes applied then seem to still be in use in HTTP_Request2_Response::decodeGzip()
This may be a duplicate of [http://framework.zend.com/issues/browse/ZF-10575] but no information was provided.