Apple 13pro keeps displaying 1.

Are you asking the reason why the text message keeps showing an unread message? Maybe it's because of the intercepted spam messages.

If you have checked all the short messages, it also means that there are unread messages mostly because spam messages are intercepted by security software. Users can access the security software to view the intercepted spam messages. Do not rule out the system failure, you can upgrade the system and then try to repair it.

You can open the information interface in the settings, click the switch button in the imessage information bar, and exit to the desktop to see that the exclamation mark on the Apple mobile phone message has been removed.