Geo map shape layer covers the whole map

Hi,

I've tried this in Design Studio 1.5 and Design Studio 1.6 and am left scratching my head. I've created a geojson file SERVICE_CONFLICTS.json that tests correctly at geojsonlint.com but when I add it to a shape layer, the entire map is filled in as chloropleth with the shapes I've defined excluded!

The tooltip shows on all of the map except for the shape in question:

Any ideas what might be causing the component to behave the exact opposite of what I'd expect?