Make sure you have filled in the real year of the event.
Custom Events in CalJ are handled in the form of anniversary reminders.
When you register a Custom Event, you must indicate the initial date of the actual event (for example for a birthday: the date of birth, with the actual year of birth), rather than the current year at registration time.
Then, because the app handles these dates as anniversary reminders, the Custom Events become visible only one year after the actual initial date of the event.