Bugs that notifications are not displayed correctly in the iPhone messaging app

You can exchange text messages using SMS and iMessage with the 'Messages' app on your iPhone. However, it has been revealed that there is a bug that the notification is not displayed correctly even if an email arrives at this messaging app.

Apple's iPhone has an aggravating text notifications bug --The Verge
https://www.theverge.com/2020/12/11/22169881/apple-iphone-ios-14-text-messages-no-notifications-bug

A bug has been reported in the messaging app for iPhone that notifications are not displayed correctly. Apple-related media Mac Rumors reported on November 13, 2020 that 'iPhone 12 and iPhone 12 Pro users are complaining about not seeing SMS notifications in the messaging app.'

iPhone 12 and 12 Pro Users Complain of Missing SMS Text Messages and Message Notifications --MacRumors
https://www.macrumors.com/2020/11/13/iphone-12-missing-sms-text-messages/

In fact, bugs have been reported since iOS 14 was released on September 16, 2020. The following post on September 19, 2020 was reported on Apple's official support forum regarding 'a bug where notifications are not displayed in the messaging app'. The reporter said, 'I ran into a bug on the iPhone 11 updated to iOS 14.' Also, the details of the bug seem to vary from user to user, with some saying 'I don't get any notifications when I'm using the phone, but I get all the notifications when I'm not using it', while others say 'iPhone. I had a problem updating my 11 Pro Max to iOS 14. Updating to iOS 14.0.1 didn't fix the problem, 'some people report.

iOS 14 text notification issues --Apple Community
https://discussions.apple.com/thread/251815788

Since bugs have been reported on multiple iPhones, it seems that the cause of the bug that the notification is not displayed in the messaging app is not from the device but from iOS 14. On Apple's official support forum and MacRumors bug report thread, 'Notifications will be sent by forcibly terminating every time you use the messaging app' and 'Notification from the destination who sent the message to the terminal for the first time' Is displayed correctly, but notifications are not displayed correctly for messages from contacts who have already exchanged messages. '

Apple plans to release the latest version of iOS 14.3 on December 14, 2020 local time, but it seems that the beta version of iOS 14.3 had a bug that notifications were not displayed in the messaging app. As a result, it's unclear if iOS 14.3 will completely fix this bug.