Heroku build loops forever

I'm trying to run a server on heroku that has a directory that looks something like

my-app
    server.js
    package.json
    client
        src
        dist
        package.json

The nested package.json has a scripts section that

  "scripts": {
    "start": "webpack-dev-server --open --mode development",
    "build": "webpack --mode production"
  },

The outer package.json has a scripts section like this

  "scripts": {
    "start": "node server",
    "build": "cd client/ && npm install && npm run build"
  },

When I push my project to heroku, I receive this output, and it just loops forever

 Build
remote:        Running build
remote:        
remote:        > my-app@1.0.0 build /tmp/build_myapp
remote:        > cd client/ && npm install && npm run build
remote:
remote:        audited 259 packages in 2.495s
remote:        
remote:        3 packages are looking for funding
remote:          run `npm fund` for details
remote:
remote:        found 1 low severity vulnerability
remote:          run `npm audit fix` to fix them, or `npm audit` for details
remote:        
remote:        > my-app@1.0.0 build /tmp/build_myapp
remote:        > cd client/ && npm install && npm run build
remote:
remote:        audited 259 packages in 2.252s
remote:        
remote:        3 packages are looking for funding
remote:          run `npm fund` for details
remote:
remote:        found 1 low severity vulnerability
remote:          run `npm audit fix` to fix them, or `npm audit` for details
remote:        
remote:        > my-app@1.0.0 build /tmp/build_myapp
remote:        > cd client/ && npm install && npm run build
remote:
remote:        audited 259 packages in 2.238s
remote:        
remote:        3 packages are looking for funding
remote:          run `npm fund` for details

from Heroku build loops forever