The theme isn't applied when you load up the restart the app. However in the settings page, the theme name is correct. It's just the colours that aren't set. For example, setting the theme to "Rashidun Caliphate" will change the theme name and colours appropriately. However, when restarting the app, the theme name still says "Rashidun Caliphate", but the colours are back to being blue, and not reddish.
The theme isn't applied when you load up the restart the app. However in the settings page, the theme name is correct. It's just the colours that aren't set. For example, setting the theme to "Rashidun Caliphate" will change the theme name and colours appropriately. However, when restarting the app, the theme name still says "Rashidun Caliphate", but the colours are back to being blue, and not reddish.