When compressing the connector sets the "Vary: Accept-Encoding". I think it would be more correct to append "Accept-Encoding" the the current value of the Vary header instead of replacing it. In particular, I cannot set this header to "Cookie" to force reload of the page if the JSESSIONID cookie changes
This has been fixed in trunk and proposed for 6.0.x
This has been fixed in 6.0.x and will be in 6.0.26 onwards.