I been using Lightning for years. In the past when I updated the attendees list, description, title

I been using Lightning for years. In the past when I updated the attendees list, description, title, location or category the attendees were informed by an update email. I have noticed in the last two or three updates to Lightning that when such changes are made the update email is not sent. I must now delete the event and re-create it by pasting it back and this causes an update email to be sent.