addLayer succeeds but nothing appears on the map

• map.getLayer('poi') exists but the circle layer draws nothing at the current zoom.
• Error: Source "poi" not found at Style.addLayer (style.ts:1204).
• querySourceFeatures('poi') returns the expected count while queryRenderedFeatures finds nothing.

1. Print map.getSource('poi'), getLayer('poi'), getLayoutProperty visibility and getFilter.
2. Call querySourceFeatures to separate no data from no style.
3. Set the filter to null and see whether features appear.
4. Check minzoom against map.getZoom() and whether an opaque fill layer covers the layer.

Add the source and layer inside load with layout: { visibility: 'visible' }, place it above the fill layers with map.moveLayer('poi-circle'), and loosen the filter before tightening it.

Error: Source "poi" not found
    at Style.addLayer (style.ts:1204)

console.log('source', map.getSource('poi'));
console.log('layer', map.getLayer('poi'));
console.log('visibility', map.getLayoutProperty('poi', 'visibility'));
console.log('filter', map.getFilter('poi'));
console.log('zoom', map.getZoom());
console.log('source features', map.querySourceFeatures('poi').length);

• Setting minzoom to 14 while the map opens at zoom 11 makes the layer look broken rather than hidden.
• Passing a single Feature instead of a FeatureCollection to the geojson source produces an empty source.