A job with catch-all rules entry triggers a Merge Request Pipeline

Summary

Creating a CI job with a catch-all rules entry (containing only a when key) causes an additional Merge Request Pipeline to be created without all the other jobs.

Steps to reproduce

Create a CI yaml file with the following content:

stages:
- build
- deploy

job1:
    stage: build
    script:
    - echo "Job 1!"
job2:
    stage: deploy
    rules:
    - if: '$CI_COMMIT_REF_NAME == "master"'
      when: always
    - when: manual
    script:
    - echo "Job 2!"

Job 1 is a compile/test job and should always run. It should especially run for merge requests.

Job 2 is a deploy job and should only run on master, or when the user wants it to on any given commit, triggered manually.

Example Project

See here: thirtythreeforty/merge-request-ci-debug!1

What is the current bug behavior?

The YAML, which makes no mention of merge_requests, creates a Merge Request Pipeline containing only a manually-executable Job 2. Job 1 is not included.

It also creates a "normal" branch pipeline containing Job 1 and Job 2 (manual).

The merge request refuses to allow the branch to be merged, because the (blocked) MR Pipeline has not finished.

What is the expected correct behavior?

For the example yaml given, no Merge Request Pipeline should be created at all, and the MR should use the normal branch pipeline containing Job 1 and Job 2 (manual).

Relevant logs and/or screenshots

Output of checks

This bug happens on GitLab.com.