Amazon AWS App Runner - Can't Run Multiple Commands Under "Build command" Config?

I have the following in my package.json file:

"scripts": {
    "migrate": "knex migrate:latest"
},

Running npm run migrate works fine on my local machine. When I try to add this command onto my existing build command:

App Runner always gives an error and rolls back my change:

Does App Runner not support multiple build commands?

The problem was a combination of running anything other than npm install in the Build command input and running more than one command in the Start command input. I ended up adding the following to my package.json file:

"scripts": {
    "migrate": "knex migrate:latest",
    "launch":  "npm run migrate && node index.js"
}

Then running them in App Runner like: