I am trying to use AdvAgg in my Drupal 7 site. I am using a local server for running tests.
After some debugging, I found out the problem: The uncompressed file didn't have a compress ratio between 0.1 and 0.9 so it was being aggregated as it was.
I'm talking exactly about advagg_js_compress.module file, lines below 143:
// Set to "-2" if compression ratio sucks (it's already compressed)