Runner stops at random place with "Cleaning up project directory and file based variables" even if there is no error

Summary

The Gitlab Runner just stops at a random place with the message

Cleaning up project directory and file based variables 00:01
ERROR: Job failed: exit code 1

Steps to reproduce

Actually I've no clue how to reproduce it because it's not deterministic.

1. See this job log that failed at showing the files from a tar cvzf command.
2. I thought it might be related somehow to the long log on a parallel pipeline and that it doesn't show the real error in step 1.
3. Thus I removed the v flag from my tar command in the Dockerfile to reduce the output and now the runner passes the previous step but suddenly dies with the same message at a different place (installing new apt packages).

Example Project

https://gitlab.com/freepascal.org/fpc/docker

What is the current bug behavior?

The Gitlab Runner randomly stops during building docker images while local creation of these images works fine.

docker buildx build -f Ubuntu/Dockerfile . 

docker buildx build -f AlpineLinux/Dockerfile . 

What is the expected correct behavior?

The Gitlab Runner shouldn't stop suddenly without any error (or at least print an error message but I doubt there is one).

Relevant logs and/or screenshots

#14 21.54 Setting up build-essential (12.8ubuntu1.1) ...
#14 21.55 Setting up libalgorithm-diff-xs-perl (0.04-6) ...
#14 21.56 Setting up libalgorithm-merge-perl (0.08-3) ...
#14 21.58 Setting up libldap-2.4-2:amd64 (2.4.49+dfsg-2ubuntu1.9) ...
#14 21.59 Setting up dirmngr (2.2.19-3ubuntu2.2) ...
#14 21.75 Setting up gpg-wks-client (2.2.19-3ubuntu2.2) ...
#14 21.76 Setting up gnupg (2.2.19-3ubuntu2.2) ...
#14 21.76 Processing triggers for libc-bin (2.31-0ubuntu9.9) ...
Cleaning up project directory and file based variables 00:01
ERROR: Job failed: exit code 1

Output of checks

This bug happens on GitLab.com

gitlab-runner 15.4.0~beta.5.gdefc7017 (defc7017) on green-2.shared.runners-manager.gitlab.com/default 

$ docker version
Client:
 Version:           20.10.17
 API version:       1.41
 Go version:        go1.17.11
 Git commit:        100c701
 Built:             Mon Jun  6 22:56:42 2022
 OS/Arch:           linux/amd64
 Context:           default
 Experimental:      true

Server: Docker Engine - Community
 Engine:
  Version:          20.10.17
  API version:      1.41 (minimum version 1.12)
  Go version:       go1.17.11
  Git commit:       a89b842
  Built:            Mon Jun  6 23:01:45 2022
  OS/Arch:          linux/amd64
  Experimental:     true
 containerd:
  Version:          v1.6.6
  GitCommit:        10c12954828e7c7c9b6e0ea9b0c02b01407d3ae1
 runc:
  Version:          1.1.2
  GitCommit:        v1.1.2-0-ga916309f
 docker-init:
  Version:          0.19.0
  GitCommit:        de40ad0