Fix bug.

app/controllers/admin/announcements_controller.rb

@@ -635,6 +635,7 @@ class Admin::AnnouncementsController < OrbitAdminController
     params.require(:announcement_setting).permit!
   end
   def update_calendar(bps,bulletin)
+    bps = bps.to_h.with_indifferent_access
     if bps[:add_to_calendar] == '0' && !bps[:event_id].blank?
       Event.find(bps[:event_id]).destroy rescue nil
       bps[:event_id] = nil

app/models/bulletin.rb

@@ -38,6 +38,9 @@ class Bulletin
   SubPart.class_eval { include BulletinModel::Cache }
   Page.class_eval { include BulletinModel::Cache }
   before_destroy do
+    if self.event_id.present? && !defined?(Calendar).nil?
+      Event.where(:id=>self.event_id).destroy
+    end
     AnnsCache.all.destroy
   end
   field :is_edit, type: Boolean, default: false #use to check whether the preview record changed