The icons on the navigation bar seem to change from sharp to blurry, depending on what page you are on in the app.
If you look at the home screen, the Robux icon seems to be burry, but when you go to Settings > About the Robux icon magically gets sharper.
There is also a problem with the icons just being blurry and sized incorrectly throughout the app. An example would be the icons on the navigation bar in the character customization screen. The shopping bag icon is blurry and slightly larger than the notification bell.
These screenshots were taken on the latest build released on the iOS App Store.