When entering a YouTube URL to Facebook or Twitter, the auto-populated video title, description, or thumbnail may occasionally be blank or out of date. This can happen when a YouTube video is entered into a post before the video has finished processing or while the video is private. You may have also updated your thumbnail or metadata on YouTube after sharing the post on a third-party website. 

Occasionally, even after the video has finished processing and is made public, an out-of-date title, description, or thumbnail may appear. This will eventually fix itself once Facebook or Twitter updates its cache.

How to update the title or description immediately

Facebook

If you are the uploader and want to ensure that other users will see the correct title and description when sharing your video on Facebook, you can enter the video URL in the Facebook debug tool to immediately update the cached title and description.

If you run into other issues, consider reporting the issue to Facebook.

Twitter

If you are the uploader and want to ensure that other users will see the correct title and description when sharing your video on Twitter, you can enter the video URL in the Twitter Card Validator to immediately update the cached title and description.

How to avoid this issue

When you upload a video, make sure that the video is processed, made public, and that the video information and thumbnail are set on YouTube before pasting the video link on a third-party website or app. Pasting the link will load the video information at that moment into the cache. Even if the title or description is changed on YouTube, the old information will persist for anybody who pastes that URL until the cache is updated.

* Nguồn: Youtube