Prefill variables in manual pipelines throwing yml syntax error

Summary

Trying to setup the "Prefill variables in manual pipelines" and it throws "This GitLab CI configuration is invalid: jobs:stage1:variables:stage1 config uses invalid data keys: options, description." error.

Steps to reproduce

1. Create .gitlab-ci.yml file
2. Define a Stage
3. Create the Stage
4. Add the variables section and add the "values, options and description" as in the document provided by GitLab.

Example Project

stages:
  - stage1
  - stage2

stage1:
  stage: stage1
  variables:
    STAGE1:
      value: "Stage 1"
      options:
        - "Stage 1"
      description: "The deployment target. Set to 'staging' by default."
  script:
    - echo "This is $STAGE1 and the job has run successfully"

stage2:
  stage: stage2
  variables:
    STAGE2: "Stage 2"
  script:
    - echo "This is $STAGE2 and the job has run successfully"

What is the current bug behavior?

When the above .gitlab-ci.yml file is created, it throws the "This GitLab CI configuration is invalid: jobs:stage1:variables:stage1 config uses invalid data keys: options, description." error.

What is the expected correct behavior?

It should not throw the syntax error and should populate the valued in the pipeline when manually run.

Relevant logs and/or screenshots

Output of checks

This bug happens on GitLab.com