disable env variable substitution in docker compose env files

I updated docker and notice a significant change of behavior when using my env files in docker-compose

I have the following:

env_file:
      - ./file.env

and, in file.env

property=${something}

Before updating, doing echo $property in my running container would produce the string ${something}. Which was what I wanted.

Now (docker 19.03.12), $property is empty because docker is trying to find $something from my system env variables.

What caused this change of behavior? Is there a way to disable it or work around it?