Original battery supplied in iPhone SE2 was failing. I had battery replaced at local IFix It and new non Apple battery showed an error in settings?
iPhone 5, iOS 9
An explanation of that message is in the article 'About genuine iPhone batteries' --> About genuine iPhone batteries - Apple Support
"An Unknown Part message will appear if the battery installation is incomplete or if the battery:
• Was replaced with a nongenuine battery
• Was already used or installed in another iPhone
• Isn't functioning as expected"
"You will see a notification on your Lock screen for the first 4 days that you use your device and in the Settings app for 15 days. After that period, you can find the notification by going to Settings > General > About." - Apple Recommended reply by ASC contributor ckuan https://discussions.apple.com/thread/253100787?answerId=255812114022#255812114022
Replaced battery in iPhone SE2 with generic battery and there is a warning now in settings?
