Alerts Disappear

Alert settings disappear. I have Sonoma on my Macbook and the latest update on my iPhone. When i go to my calendar my birthdays populate properly (I selected this option.) In my calendar I select 1 week and day of alerts on the calendar ( I like to send birthday cards) and then they later disappear, I get no notifications, yet it is coming from the fact the the alerts settings have disappeared. I reset the alerts and they disappear again. I do not know how long it is before they disappear.

Please help.