GeoJSON displaying as a blue patch in reference layer of Azure map

Hi all,

I added a GeoJSON file with NUTS regions as a reference layer in Azure map (not ArcGIS map), but it is showing as a blue patch instead of lines, see picture below.

I downloaded the GeoJSON here with the following options selected:

In Mapshaper it is rendering fine, see picture.

On MyGeodata I checked if the coordinates in the json are maybe not WGS84, but they are, see picture below.

I tried adjusting the colors in the formatting pane but that doesn't even change the color, let alone show lines instead of a patch.

So what's happening here? Why is it not displaying the same way as in Mapshaper ? Can someone give me some clues? Many thanks in advance!