I poked around a whole bunch to see if I could find a bitrate listing or something useful but I couldn't find anything. I am not an Amazon Music user so I've run out of ideas.
I did test a bunch more just to see for certain but actually I couldn't definitively reproduce this as an Orion bug. I have had some instances where the music playing from Safari was low quality and Orion was fine. Perhaps this is a WebKit bug?
In my testing I did try to switch useragents around just to see but Amazon was returning errors for almost all of them:
