Many new iPhone users who upgraded to iPhone X and used their old iPhone backup are seeing an issue that they are noticing the battery widget (from the swipe down menu) says “iPhone 6s Plus” ( or the old iPhone model they have).
It’s just displaying the wrong phone description it has the iPhone X symbol next to it. Other than this issue users do not see anything other issue with backup import from old iPhone. Not that this is a bug,
It is quite possible that importing an iCloud backup onto a new device bring over the same glitches and/or bugs from the previous device.
To Correct the name in iPhone X battery widget please Go to settings - general - about Then change the name of your iPhone to whatever you want. This will fix the issue.