In Gitlab, need to pass a variable containing special character “$” to another stage via artifacts.

What I tried:

build:
  stage: build
  script:
    - my_var='Admini$trator'
    - echo "pass=$my_var" >> build.env
  artifacts:
    reports:
      dotenv: build.env 

test:
  stage: test
  needs:
    - job: build
      artifacts: true
  script:
    - echo $pass 

The output is “Admini” instead of “Admini$trator”.
I also tried escaping with backslash “Admini$trator” but I get “Admini”.

What is the correct way to escape artifact variables?