Yeah I’ve brought up the “wind tunnel” occurring during the Emperor’s arrival before. The music is actually a hodgepodge of 3 different cues, and NONE of the source material has that flanging, phasing in and out effect. That tells me that it luckily didn’t happen at the scoring sessions, but at some point when being mixed down for God-knows how many prints were going to be produced. I have yet to experience ANY copy of that part of the film that this is fixed. It drives me nuts as an “audio guy”, but unfortunately it was used as the master for umpteen million releases, even the BD. If it were up to me and I knew how to work with video, I would assemble the track and put it in the film. But, it is what it is. Something happened in mastering and mixing that made the speed of the film change slightly from the sound going on at the same time or vice versa. So yes, Ben Burtt makes mistakes like everyone else.
Here’s the Wikipedia page about flanging, and there is a sample to play as well.