Hi, all.
Just experienced this issue. The quick fix I found was to use the Pause Live TV function. Buy a 16 GB USB flash drive (should cost $10 or less) and plug it into your TV. Set up Pause Live TV. Now when you access OTA channels and you get choppy audio, use the remote to pause for a couple seconds and then unpause. In my experience this has worked consistently consistently to get rid of the choppy audio. Unfortunately, it's not permanent solution as you have to pause and unpause every time you access the choppy channel(s), but it might mean you don't have to throw out the TV.
For reference, I'm on a Sharp Roku TV (LC-43LB371U) and my choppy audio was from channel 2 KATU (ABC - Portland, OR)