Browsers store video detection data in memory. If this storage becomes cluttered or "stale," it may point to segments that no longer exist on the server.
Your antivirus might be blocking the avd-host.exe or its temporary folder. Add the following folder to your antivirus exclusion list: ant video downloader downloaded segment is empty
AVD relies on a "Native App" to handle complex video assembly. If segments are empty, the link between the browser and this app might be broken: Browsers store video detection data in memory