CI ignores "when" and "except" in .gitlab-ci.yml

Summary

Gitlab CI seems to ignore the in the .gitlab-ci.yml defined conditions in "when" and "except" (at least some).

Simular issue raised by someone else in support forum: https://gitlab.com/gitlab-com/support-forum/issues/4949

Steps to reproduce

Run pipeline which defines such conditions, like Auto-DevOps.

Example Project

What is the current bug behavior?

All possible stages are executed.

What is the expected correct behavior?

Only the defined (by when/except) stages should be executed.

Relevant logs and/or screenshots

Output of checks

Results of GitLab environment info

I'm testing on gitlab.com

Possible fixes