This is a Next.js project bootstrapped with create-next-app.
The error seems to be intermittent. If you don't see it on the first builds, keep deleting the .next folder and re-build. I get it pretty consistently, but sometimes it won't throw the warning.
# Make sure you are on latest Yarn version (>2.0.0).
yarn set version stable
# Install dependencies specified in package.json
yarn install
# Build the application
yarn build
# Build Docker container
yarn docker:build