I removed all debug output from the gist linked above and added code to check if the $content passed through the output buffer is gzipped and if so, unzips it.
All of this based on the "content encoding error" with the previous debug-version, which can only be explained by the content being gzipped when AO receives it from the output buffer (which also explains why AO doesn't do anything with in the first place).
Can you give https://gist.github.com/futtta/10373800354595e3f395 a go? :-)