App icon switches to low resolution upon launching an app
This appears to be a bug in the app itself. It's also affecting the Wolfram app and affects not only the icon in the dock, but also the app switcher icon. I tried creating a new WolframDesktop.icns file, but the application still reverts back to the lower resolution icon on my 13" MacBook Pro. The icon renders fine on a 15" MacBook Pro. Both are running Mojave.