electron-builder: download-progress does not emit proper values (nsis-web, differentialPackage)

I have problem with update events when using nsis-web. The thing is that download-progress event is only taking into consideration the .exe file which is 500KB and when I want to display some progressbar it is downloading 500KB and showing instantly 100%. After that it is downloading 7z file in the background and I cannot see progress of it - this is bad especially as I plan to have large files included in app.

package.json

  "scripts": {
    "publish": "build --x64 --ia32 --windows nsis-web -p always"
  },
  "devDependencies": {
    ...
    "electron": "1.7.10",
    "electron-builder": "19.54.0",
    "electron-publisher-s3": "^19.55.2"
  },
  "dependencies": {
    ...
    "electron-log": "2.2.14",
    "electron-updater": "2.20.0"
  }

electron-build.json

{
  "appId": "com.kkl.test",
  "publish": [
    {
      "provider": "s3",
      "bucket": "somebucket",
      "region": "eu-central-1"
    }
  ],
  "productName": "test",
  "directories": {
    "output": "app-builds"
  },
  "win": {
    "target": [
      "nsis-web"
    ]
  },
  "nsisWeb": {
    "differentialPackage": true,
    "oneClick": false,
    "perMachine": true,
    "allowElevation": true,
    "allowToChangeInstallationDirectory": true,
    "unicode": true,
    "runAfterFinish": true,
    "deleteAppDataOnUninstall": true
  }
}

log.log file:

[2018-01-24 21:29:57.751] [info] Found version 0.0.4-test (url: test Web Setup 0.0.4-test.exe)
[2018-01-24 21:29:57.751] [info] { info: 
   { version: '0.0.4-test',
     files: [ [Object] ],
     path: 'test Web Setup 0.0.4-test.exe',
     sha512: 'jcijdawbJlHYIm6vf43RQeMTm1QLMhjZ1J3rviGW6XRwvd/J7Q3RC6I4zihJjh97CjUe+KJ7X1H/5WVLICLlKw==',
     packages: { ia32: [Object], x64: [Object] },
     sha2: 'c9e920597c31b826e332614ac824a69dc30bd0b01586fce737fe4fe09eca4153',
     releaseDate: '2018-01-24T15:47:49.189Z' },
  type: 'update-available' }
[2018-01-24 21:29:57.753] [info] Downloading update from test Web Setup 0.0.4-test.exe
[2018-01-24 21:29:58.064] [info] { progressObj: 
   { total: 511884,
     delta: 511884,
     transferred: 511884,
     percent: 100,
     bytesPerSecond: 2337370 },
  type: 'progress' }
[2018-01-24 21:29:58.709] [info] File has 10350 changed blocks
[2018-01-24 21:29:58.713] [info] Full: 246,918.68 KB, To download: 211,158.25 KB (86%)
[2018-01-24 21:29:58.718] [info] Differential download: https://bucket.s3.amazonaws.com/somefile-0.0.4-test-x64.nsis.7z

Is there a way to use differentialPackage and nicely show download progress of all files? Or maybe there is something wrong in my setup ?