iPhone 15 Calendar: Add Attachment button missing

Iphone 15, iOS 26.4.2.

I created a calendar event. I want to add an attachment but the “Add Attachment” button is not present. I f I create another event the “add attachment” button comes up. I suppose I need to make another event and just chalk it up to a program bug. I see many people who have the same problem but there is no solution that works for them or me.