Google announced on Twitter that it made a change to how Google Search Console reports on your video structured data. Specifically, Google wrote "if you use video structured data, our reporting is now aligned with the docs and will warn if neither embedUrl nor contentUrl is used in a VideoObject."
Here is the tweet:
📺 A brief heads-up on a Search Console reporting change: If you use video structured data, our reporting is now aligned with the docs and will warn if neither embedUrl nor contentUrl is used in a VideoObject. Find out more at https://t.co/OUNShrOWTc
— Google Webmasters (@googlewmc) July 2, 2020
The docs say "we recommend that you provide a URL to your video. You can provide a URL by using one or both of the following properties: contentUrl and embedUrl." So I guess if you are not doing this, Google will let you know in Google Search Console?
The data anomalies page explained:
Search Console began marking as "warning" any Video object that is missing both embedUrl and contentUrl properties. This is not a change in requirements or behavior, but an improvement in our reporting system to better reflect the actual indexing behavior. Video objects that are missing both embedUrl and contentUrl properties can still appear as rich results but additional content based features of videos such as animated previews and key moments may not work. Therefore you might see an increase in warnings in Video items on your site. To fix this issue, define either of these two properties in your Video object. (Note that this does not affect Video items embedded within other types, such as Video within Recipe.)
Forum discussion at Twitter.