Airport lvl 3 not showing on map

Hi, I just noticed that whenever I upgrade an airport to level 3, it disappears from the map as icon.

it's build and functions, there is just no longer an icon to represent on the map that there is an airfield present.

Kind of hard (and annoying) to check the provinces manually if you want to relocate your planes.

Level 1 and 2 airports are shown as icon on the map.