Embedded Links in Discussion Thread Posts are not dynamically and programmatically connected to a piece of content, so that when that piece of content is update, it magically updates posts, comments, reviews, profile posts, conversations (anything with a message field that uses the Core XF Editor) that might have a LINK to that piece of content.
Now if the post was using a custom BBCode, then that would render each time someone fetched the thread. Sportsbook does not have a custom bbcode for Events, Outcomes or Bets like other addons of mine have.
UNFURL is handled during the SAVE (Create and Edit) process of a given discussion thread post.
If you are talking about something else, please clarify