fixedWindowRollup produces error

[Mottoweb]

const resolutionWindow = window(duration("1d"));
  const bars = series.fixedWindowRollup({
    window: resolutionWindow,
    aggregation: {
      c: { c: avg() } as unknown as Aggregation<Key>,
    },
  });

produces:

TypeError: Cannot read properties of null (reading 'window')

using 1.0.0-alpha.10