We have an issue where the sound is slightly off from the picture (not just at our cinema), but despite that we only had one person complain. Just because she was the only one to complain about it, doesn't mean she was wrong or didn't have something to complain about.
Omfg I noticed that too. It was so so jarring, eugh. Almost as bad as a Wilhelm Scream.
I watched it in Lower Hutt and never noticed it, I'd walked in and out of the movie so many times at work and never noticed it, then the lady complained and I looked very closely and noticed it clear as day. After that, it's all I notice when I walk in haha funny how the brain corrects things I suppose.
Poor lady (and you) though, it must have driven her nuts.
But clearly it wasn't a valid complaint, because she was the only one to complain.