Prefilled values of the variables in a `ci` file of a parent pipeline are passing to a child pipeline

Summary

Prefilled values of the variables in a ci file of a parent pipeline are passing to a child pipeline

Steps to reproduce

Pipeline with an example of the behavior - https://gitlab.com/arsh1697/downstream-pipeline/-/pipelines/286563160

  1. Copy my example project - https://gitlab.com/arsh1697/downstream-pipeline.
    It's a simple project with parent pipeline which is run from .gitlab-ci.yml file.
    Parent pipeline triggers child pipeline. Ci file for child pipeline is generated-ci.yml

  2. Default value for variable PREDEFINED_VARIABLE - “predefined” Run pipeline with this parameters - image

  3. Check logs of the "fake-generate" (parent) job.
    image

  4. Check logs of the "test" (child) job.
    image

Example Project

Project - https://gitlab.com/arsh1697/downstream-pipeline.

What is the current bug behavior?

The prefilled value of the variable in the ci file of the parent pipeline is passing to the child pipeline

What is the expected correct behavior?

The prefilled value of the variable in the ci file of the parent pipeline is NOT passing to the child pipeline.

Let's suppose that it is normal behavior that variables from parent pipeline are passing to the child pipelines. Than it's not clear why in my example "ANOTHER_VALUE"="" and value of the "PREDEFINED_VARIABLE" is equal to the prefilled value

Also I didn't find any documentation that described this behavior

Edited by Artem Sheveliukhin