Reviews widget / Goodreads Shelf widget / etc. not updating
Most Ultimate Book Blogger widgets like Reviews, Goodreads Shelf, Giveaways, etc. are cached. This means the plugin fetches the results (like list of reviews) and then saves that result for one day. This is to make your site load faster and avoid expensive database queries on every page load. Because of this, your widgets may not update instantly when you publish a new review, or adjust your Goodreads shelf, etc.
If for some reason you need to update the widget immediately, then Save it. This clears the cache and forces it to refresh immediately.