iOS 18.1 Color scheme bug
Here’s a description you can use to report the bug:
Bug Description: In iOS 18.1, when changing the color scheme of app icons from the lock screen while an app (e.g., Spotify) is running in the background, the icon for the background app does not update to reflect the new color scheme. Instead, it retains the color from the previous scheme, creating an inconsistency in the icon display.
iPhone 14 Pro, iOS 18