inverse globbing in .gitlab-ci.yml does not pick up changes

Summary

I have a job which needs to be executed when any file, in any directory is modified EXCEPT for files in special_dir. We should ignore all changes made inside the special_dir, except we will allow changes to anything inside special_dir/allowed_folder

The following syntax is picked up correctly

  only:
    changes:
      - "*"
      - special_dir/allowed_folder/**/*
      - "./!(special_dir)/**/*"

Example directory structure, with file extensions indicating if a file should trigger the pipeline or not. The yellow files should be picked up by the globbing above, but are not

Steps to reproduce

In the directory structure above, modifications to a_folder and its subdirectories are not picked up by the pipeline, even though they should be

Example Project

https://gitlab.com/sgrimes-stackod/example-inverse-glob-failure

What is the current bug behavior?

Modifying a_folder/file.allowed does not trigger the job

What is the expected correct behavior?

Modifying a_folder/file.allowed triggers the job

Relevant logs and/or screenshots

a_folder/file.allowed should be picked up by the glob "!(special_dir)/**/*"

Output of checks

This bug happens on GitLab.com

(If you can, link to the line of code that might be responsible for the problem)