Piping into 'tail' first seems to cause out-of-order execution

Summary

Piping into tail first seems to cause out-of-order execution when working with multiple piped operations.

Steps to reproduce

The following CI YAML has everything to reproduce this issue.

.gitlab-ci.yml

variables:
  MESSAGE: |
    git@example.com:group/project
    subscription: sub1
    location: loc1

.shared-scripts:
  set-vars: &set-vars
    - >
      SUBSCRIPTION=$(echo "$MESSAGE" | tail -n 2 | head -n 1 | cut -d " " -f 2);
      LOCATION=$(echo "$MESSAGE" | tail -n 1 | cut -d " " -f 2);

anchored-job:
  before_script:
    - *set-vars
  script:
    - echo "'${SUBSCRIPTION}'"  # does not work
    - echo "'${LOCATION}'"  # does not work

regular-job-tail-first:
  before_script:
    - >
      SUBSCRIPTION=$(echo "$MESSAGE" | tail -n 2 | head -n 1 | cut -d " " -f 2);
      LOCATION=$(echo "$MESSAGE" | tail -n 1 | cut -d " " -f 2);
  script:
    - echo "'${SUBSCRIPTION}'"  # does not work
    - echo "'${LOCATION}'"  # does not work

regular-job-head-first:
  before_script:
    - >
      SUBSCRIPTION=$(echo "$MESSAGE" | head -n 2 | tail -n 1 | cut -d " " -f 2);
      LOCATION=$(echo "$MESSAGE" | tail -n 1 | cut -d " " -f 2);
  script:
    - echo "'${SUBSCRIPTION}'"  # works
    - echo "'${LOCATION}'"  # does not work

regular-job-more-pipes:
  before_script:
    - PROJECT=$(echo "$MESSAGE" | head -n 1 | cut -d ":" -f 2 | rev | cut -d "/" -f 1 | rev)
  script:
    - echo "'${PROJECT}'"  # works

Actual behavior

What is happening is that instead of every piped operation being applied in the order they are specified, some are being done in an order that is not expected. When looking at the debug output the following is apparent:

regular-job-tail-first

+++ echo 'git@example.com:group/project
subscription: sub1
location: loc1
'
+++ head -n 1
+++ tail -n 2
+++ cut -d ' ' -f 2
++ SUBSCRIPTION=loc1

+++ echo 'git@example.com:group/project
subscription: sub1
location: loc1
'
+++ cut -d ' ' -f 2
+++ tail -n 1
++ LOCATION=

Expected behavior

The order of execution should be deterministic. The SUBSCRIPTION and LOCATION command substitutions should yield sub1 and loc1, respectively.

Relevant logs and/or screenshots

anchored-job

$ SUBSCRIPTION=$(echo "$MESSAGE" | tail -n 2 | head -n 1 | cut -d " " -f 2); LOCATION=$(echo "$MESSAGE" | tail -n 1 | cut -d " " -f 2);
$ echo "'${SUBSCRIPTION}'"
'loc1'
$ echo "'${LOCATION}'"
''

regular-job-head-first

$ SUBSCRIPTION=$(echo "$MESSAGE" | head -n 2 | tail -n 1 | cut -d " " -f 2); LOCATION=$(echo "$MESSAGE" | tail -n 1 | cut -d " " -f 2);
$ echo "'${SUBSCRIPTION}'"
'sub1'
$ echo "'${LOCATION}'"
''

regular-job-tail-first

$ SUBSCRIPTION=$(echo "$MESSAGE" | tail -n 2 | head -n 1 | cut -d " " -f 2); LOCATION=$(echo "$MESSAGE" | tail -n 1 | cut -d " " -f 2);
$ echo "'${SUBSCRIPTION}'"
'loc1'
$ echo "'${LOCATION}'"
''

regular-job-more-pipes

$ PROJECT=$(echo "$MESSAGE" | head -n 1 | cut -d ":" -f 2 | rev | cut -d "/" -f 1 | rev)
$ echo "'${PROJECT}'"
'project'

Environment description

Using shared Runners for reporting this particular issue, but discovered this issue whilst using Runners on GCP.

Used GitLab Runner version

Shared Runner:

Running with gitlab-runner 14.4.0-rc1 (bc99a056)
  on docker-auto-scale 72989761

Private Runner:

Running with gitlab-runner 14.3.2 (e0218c92)