How do I enable SSI with Apache and mod_jk / mod_proxy ?

Issue

• SSI include doesn't work correctly

• "[an error occurred while processing this directive]" message appears on the html output

• "unable to include "[filename]" in parsed file [resuested path]" message in the Apache HTTPD error_log
• [filename] part in the above message is corrupted, looks something mixed with the other random part of the response
• Always reproducible with specific response, not a concurrent issue