Maplibre and 3d terrain

[gorbypark]

I'm attempting to get maplibre to work with 3d terrain using react-map-gl. I've gotten the terrain control working, and when clicking on enable terrain, I can see the DEM tiles being loaded in the network monitor, but no terrain shows up. No errors in the console and no other clues as to why it's not showing up. The style was taken from this (working) example: https://maplibre.org/maplibre-gl-js-docs/example/3d-terrain/

import React from 'react';
import 'maplibre-gl/dist/maplibre-gl.css';
import ReactMapGl, {NavigationControl, useControl} from 'react-map-gl';
import maplibregl, {TerrainControl as MLTerrainControl} from 'maplibre-gl';

const Map = () => {
  const TerrainControl = () => {
    useControl(
      () =>
        // @ts-ignore
        new MLTerrainControl({
          source: 'terrainSource',
          exaggeration: 1,
        }),
    );
    return null;
  };

  return (
    <ReactMapGl
      mapLib={maplibregl}
      initialViewState={{
        longitude: 11.39085,
        latitude: 47.27574,
        zoom: 14,
        pitch: 52,
      }}
      maxPitch={85}
      style={{flex: 1}}
      mapStyle={{
        version: 8,
        sources: {
          osm: {
            type: 'raster',
            tiles: ['https://a.tile.openstreetmap.org/{z}/{x}/{y}.png'],
            tileSize: 256,
            attribution: '&copy; OpenStreetMap Contributors',
            maxzoom: 19,
          },
          terrainSource: {
            type: 'raster-dem',
            url: 'https://demotiles.maplibre.org/terrain-tiles/tiles.json',
            tileSize: 256,
          },
          hillshadeSource: {
            type: 'raster-dem',
            url: 'https://demotiles.maplibre.org/terrain-tiles/tiles.json',
            tileSize: 256,
          },
        },
        layers: [
          {
            id: 'osm',
            type: 'raster',
            source: 'osm',
          },
          {
            id: 'hills',
            type: 'hillshade',
            source: 'hillshadeSource',
            layout: {visibility: 'visible'},
            paint: {'hillshade-shadow-color': '#473B24'},
          },
        ],
      }}
      terrain={{
        source: 'terrainSource',
        exaggeration: 1,
      }}>
      <NavigationControl visualizePitch />
      <TerrainControl />
    </ReactMapGl>
  );
};

export default Map;