Zip size is much larger on cdci than locally

I have an issue where the size of the zipped lambdas are much larger on the cdci (GitLab CE 11.8.0) than when running the package script locally.
The lambdas are written in typescript and I use serverless-webpack to decrease the size as much as I can.
I have not written the code so I don’t know why they are so large
but still I think there should not really be that big of a difference between local and cdci packaging?

Am I missing something?
Here is the build log: https://pastebin.com/pcG7QaAg

Size when running serverless package locally:
getReport.zip: 28.6 MB
push.zip: 25.8 MB
alerts.zip: 25.8 MB
reporting: 5 MB
user.zip: 2.3 MB
imageupload.zip: 90 KB

Size when running serverless deploy on cdci:
getReport.zip: 168.76 MB
push.zip: 92.91 MB
alerts.zip: 92.91 MB
reporting: 4.7 MB
user.zip: 2.08 MB
imageupload.zip: 55.68 KB

serverless.yml:
plugins:
- serverless-dotenv-plugin
- serverless-offline
- serverless-plugin-aws-alerts
- serverless-plugin-info-json
- serverless-webpack

package:
  individually: true
  exclude:
    - node_modules/aws-sdk/**

provider:
  name: aws
  region: eu-west-1
  runtime: nodejs10.x
  memorySize: 512
  timeout: 30
  versionFunctions: false
  stage: ${opt:stage, 'dev'}
  apiGateway:
    shouldStartNameWithService: true

custom:
  webpack:
    webpackConfig: ./webpack.config.js
    includeModules: true

.gitlab-ci.yml:

.deploy_to_aws:
  image: node:latest
  script:
    - npm i -g serverless
    - npm ci
    - serverless config credentials --provider aws --key $AWS_ACCESS_KEY_ID --secret $AWS_SECRET_ACCESS_KEY
    - serverless deploy --verbose --stage $STAGE --region $AWS_DEFAULT_REGION

webpack.config.js

const path = require("path")
const slsw = require("serverless-webpack")
const nodeExternals = require("webpack-node-externals")

module.exports = {
  context: __dirname,
  mode: slsw.lib.webpack.isLocal ? "development" : "production",
  entry: slsw.lib.entries,
  resolve: {
    extensions: [".ts"],
    symlinks: false,
    cacheWithContext: false,
  },
  output: {
    libraryTarget: "commonjs",
    path: path.join(__dirname, ".webpack"),
    filename: "[name].js",
  },
  target: "node",
  externals: [nodeExternals()],
  module: {
    rules: [
      {
        test: /\.(ts)$/,
        loader: "ts-loader",
        exclude: [
          [
            path.resolve(__dirname, "node_modules"),
            path.resolve(__dirname, ".serverless"),
            path.resolve(__dirname, ".webpack"),
          ],
        ],
        options: {
          transpileOnly: true,
          experimentalWatchApi: true,
        },
      },
    ],
  },
}