No dialog on HBO MAX Billy Joel documentary

I’m trying to watch the new Billy Joel documentary on HBO MAX from my AppleTV 4k with a Vizio soundbar. All I get is a background track, with no dialogue. It plays fine on my iPad Mini on the HBO MAX app. However, when. I use mirroring to move it to the AppleTV, the dialogue once again goes away. Other shows on the channel are playing fine. Any troubleshooting tips?