Attribution icon displays on map with no Mapbox styles/tiles only when screen is less than 641 pixels wide.

[gorbypark]

When a map is using self hosted styles and tiles, the attribution icon is hidden unless the screen is less than 641 pixels wide. When clicked, it displays an empty small white rectangle. Tested on Chrome 63, Firefox 57 and Chrome on Android using mapbox-gl-js 0.43.0. I suspect the expected behaviour is the icon to be hidden at all times when not using Mapbox based styles/tiles.