Classes will disappear after the final WordPress event instance of the class, AND typically you register for all class sessions at once so we only want one Ticketing URL for the registration.
What we recommend is to create one event instance for each class session, so the class will stay active on the site until the class is over. Since those event instances are created manually in WordPress, you only put the registration URL in the first event instance, which closes registration either when the class sells out or after the first class session begins. The site looks for this specific situation with classes and also pulls this first Ticketing URL for the general Register buttons.
The final product looks something like this:
There's a second benefit to doing things this way - you can turn on a weekly or mini class calendar on the page and then students and parents can see the whole class schedule on the page.