In order to make sure the front end website updates when you swap or remove emergency bulletins, make sure you set the expire date for a future time.If you set it to a time in the past, the App side will update as it's referencing what is active, but the public facing side may not, as the server is keeping it up until the expire date passes.
If you are removing an emergency bulletin, make sure the time is set slightly in the future. For example, if the time is currently 2:30pm, set it to expire at 2:32pm or later. If you are putting a new bulletin up at that time, make sure it's publish time is set to the same as the expire time of the previous bulletin. Setting the expire date for in the past may cause the old bulletin to continue to display.