exceljs: workbook.xlsx.writeBuffer() silently breaks since v1.11.0, only in production

I have a hard time believing what is happening to me: After getting error complaints from users I found that exports are silently failing. Only in production. It works fine in dev mode!?

After some debugging I could narrow it down to the await workbook.xlsx.writeBuffer() line in this module of mine, as console.log nr. 5 is the last to appear in production:

import * as ExcelJs from 'exceljs/dist/exceljs.min.js'

import getDataArrayFromExportObjects from './getDataArrayFromExportObjects'

export default async ({ data, store }) => {
  console.log('getXlsxBuffer 1')
  const dataArray = getDataArrayFromExportObjects(data)
  console.log('getXlsxBuffer 2', { dataArray })
  const numberOfColumns =
    dataArray && dataArray[0] && dataArray[0].length ? dataArray[0].length : 0
  const workbook = new ExcelJs.Workbook()
  console.log('getXlsxBuffer 3', { workbook })
  const worksheet = workbook.addWorksheet('Daten', {
    views: [
      {
        state: 'frozen',
        xSplit: 0,
        ySplit: 1,
      },
    ],
    autoFilter: {
      from: {
        row: 1,
        column: 1,
      },
      to: {
        row: 1,
        column: numberOfColumns,
      },
    },
  })
  worksheet.addRows(dataArray)
  worksheet.getRow(1).fill = {
    type: 'gradient',
    gradient: 'angle',
    degree: 0,
    stops: [
      { position: 0, color: { argb: 'FFD3D3D3' } },
      { position: 1, color: { argb: 'FFD3D3D3' } },
    ],
  }
  worksheet.getRow(1).font = {
    bold: true,
  }
  worksheet.getRow(1).border = {
    bottom: {
      style: 'thin',
    },
  }
  console.log('getXlsxBuffer 4')
  let buffer
  try {
    console.log('getXlsxBuffer 5')
    buffer = await workbook.xlsx.writeBuffer()
    console.log('getXlsxBuffer 6')
  } catch (error) {
    console.log('getXlsxBuffer, error:', error)
    return store.enqueNotification({
      message: error.message,
      options: {
        variant: 'error',
      },
    })
  }
  console.log('getXlsxBuffer 7', { buffer })
  return buffer
}

I then started rolling back versions and found that it works fine in v1.10.0 in production.

Some more info:

• my project: https://github.com/barbalex/apf2
• developed on windows 10, up to date
• Gatsby project
• hosted on zeit/now