If you update something about a video on one of our third-party supported platforms (i.e. thumbnail for the video, title, description, etc.), it does not update on your liveBooks site automatically. You must embed the code again in order for the updates to be reflected on the site.
If you update the thumbnails on the Vimeo website and the videos have already been added into the Video gallery block on liveBooks, they will not update in sync. The way to fix this is to delete and add the videos into the block once more.