Gitlab runner randomly can't clone repository : HTTP Basic: Access denied

Summary

While doing a pipeline, some task randomly fails due to gitlab-ci-token which seems to be unable to clone the repository.

Relevant logs and/or screenshots

Running with gitlab-ci-multi-runner 1.11.1 (a67a225)
  on ci-runner01 (2591046a)
Using Shell executor...
Running on ci-runner01..
Fetching changes...
Removing vendor/
HEAD is now at dd42fa1 Testing gitlab CI
remote: HTTP Basic: Access denied
fatal: Authentication failed for 'https://gitlab-ci-token:xxxxxxxxxxxxxxxxxxxx@gitlab.com/PROJECT/www.repo.com.git/'
Fetching changes...
HEAD is now at dd42fa1 Testing gitlab CI
remote: HTTP Basic: Access denied
fatal: Authentication failed for 'https://gitlab-ci-token:xxxxxxxxxxxxxxxxxxxx@gitlab.com/PROJECT/www.repo.com.git/'
Fetching changes...
HEAD is now at dd42fa1 Testing gitlab CI

Environment description

We are using a custom runner on gitlab.com Shell executor

Used GitLab Runner version

Git revision: a67a225
Git branch:   1-11-stable
GO version:   go1.7.5
Built:        Fri, 03 Mar 2017 12:35:58 +0000
OS/Arch:      linux/amd64```