Have you made any changes related to your event lately?
When you share your event on social media, is it not the new image, description, date, links, but the old one that appear?
Social media platforms such as Facebook and Twitter keep your event's information in their files without looking if it has changed.
Fortunately, there are tools to remedy the situation.
For Facebook, here is the procedure to follow.
For Twitter, here is the procedure to follow.
As for our site, it is possible that your changes appear only a few hours after making the change.
This is completely normal.