Unexpected behavior with dynamic inputs when using boolean type

I want to have a boolean input with dynamic rules:

spec:
  inputs:
    workflow:
      type: string
      options: ['some-other-job', 'scan-vulnerabilities']
      default: 'some-other-job'

    # Used to run vulnerability scanning
    run-vulnerability-scanning:
      type: boolean
      rules:
        - if: $[[ inputs.workflow ]] == 'scan-vulnerabilities'
          default: true

In this way, I would expect it to not be shown in the UI unless the expected workflow value is selected before.

However, the pipeline editor gives this warning: "This GitLab CI configuration is invalid: run-vulnerability-scanning input: default value is not a boolean.". So I can understand that a boolean input must always have a true/false value - fallback-default must exist. And by design, there's no way to dynamically hide it, like with string inputs?

But the issue continues: if I add the fallback-default value, like this:

    run-vulnerability-scanning:
      type: boolean
      rules:
        - if: $[[ inputs.workflow ]] == 'scan-vulnerabilities'
          default: true
        - default: false

it still shows the same warning! But it gets even more confusing: if I set it to true, the validator stops complaining. Also, if I wrap the boolean values in quotes, like 'false', it also passes the validation.

So even if the way I want to use is not supported, boolean value behavior in the fallback-default rule seems inconsistent.