Why did Apple 13 delete the SMS content and show the chat time?

The system automatically saves it for a period of time. Since the mid-term version of iOS 15, if you directly enter the SMS app to delete the SMS after receiving the SMS, the SMS notification will still exist in the notification center, and you need to manually clear the SMS notification. In addition, after deleting a message, touching the notification in the notification center will jump to the SMS app and enter the interface of writing a new message. The recipient is the original sender of the deleted message.