I have this issue as well. Really annoying. I just took delivery this weekend so I know I also have the in house audio system. Really hope it’s just software and not hardware.
A tech came out from the Chelsea, MA service center yesterday. I spoke with him on the phone beforehand and he was familiar with the problem. He said he had fixed 2 others already and that the problem was a piece of foam that sits too close to the speaker. Nothing wrong with the speaker itself. He came out, took of the speaker and re-installed it with more room between the speaker and the foam around it. It works perfectly now!