I have to add a line to Dockerfile make it work: RUN npm add @babel/runtime

Building from docker start up fails with a babel error.
I added this line to the Dockerfile and now runs:

RUN npm add @babel/runtime

Dockerfile:

FROM node:14.16.0
RUN npm install pm2
WORKDIR /src
COPY . .
RUN npm add @babel/runtime
RUN npm run setup
EXPOSE 3000

Start with the Dockerfile shown in the issue and run the image build and startup sequence using node:14.16.0, including npm run setup, while capturing the Babel error. Compare the failing build with the reported RUN npm add @babel/runtime workaround; done means the documented Docker startup works reliably without an unexplained manual step.

Written by the indexing model from the issue text.