Embedded component unable to build using vite 3.0, works in 2.0

[cmdcolin]

Tested out @jbrowse/react-linear-genome-view in vite 3.0 (newly released https://vitejs.dev/blog/announcing-vite3.html) and although it works at dev time, it fails at production build with an error

Uncaught TypeError: Class extends value #<Object> is not a constructor or null
    at index.d1b9f577.js:408:43547

code it refers to is minified but some clues

var vf = _x()
  , yn = _I()
  , Ol = Tx()
  , CX = lb()
  , xX = VG();
class cb extends CX {
    constructor() {
        super(...arguments),
        this.supportsSVG = !0
    }
    async render(t) {
        const r = await this.getFeatures(t)
          , {height: n, regions: o, bpPerPx: a} = t
          , [i] = o
          , s = (i.end - i.start) / a
          , l = await xX.renderToAbstractCanvas(s, n, t, c=>this.draw(c, {
            ...t,
            features: r
        }));
        return {
            ...await super.render({
                ...t,
                ...l,
                features: r,

this could be a vite problem or it could be something in our code, not quite sure