Can you tell me which browser headers your CDN uses to determine the browser type?
The automatic quality selection is based on an analysis of the asset itself and how the perceptual quality changes at different encoding settings. It's not based on the browser making the request, though q_auto in the URL will switch between the 'good' and 'eco' settings based on whether the browser sent a save-data header.
The automatic format feature is based on a combination of the user-agent and accept headers, and chooses a format to send based on our knowledge of that browser and its accept header indicating which formats it can show
There's a guide to both features available here: https://cloudinary.com/documentation/image_optimization