If you’re referring to the setting delete expired event posts after, I think it prevents the deletion of the post, but not the display of the event, plus I think the term event here is misleading, it’s in the calendar section so I think it means more “date related thing” than “event in the rsvp-possible sense”.
that’s a calendar-event, not an event-event
event-events are meant to be displayed in /upcoming-events hence nothing in the past…
There is a PR about that actually: FEATURE: Show all events in past (add deleted_at in discourse_calendar_post_event_dates) + add show_past_event in settings by ledadu · Pull Request #199 · discourse/discourse-calendar · GitHub