Messages notification badge on iPhone is out of sync with other devices
The unread Messages notification badge on my iPhone (14.8) is out of sync with those on my iPad (14.8) and my Mac (10.13.6); the iPad's and Mac's badges are in sync. I have logged the iPhone out of & back into iCloud, and have turned iMessage off and on again. The iPad and Mac acknowledge that the iPhone has been added, but the bad badge behavior has not changed. I've submitted feedback on the issue through Apple's Product Feedback page for iPhone.