Constant freezes in the CI

Description of the problem

CI hangs on random steps during the build. Example:

As you can see a part of this log is broken.

Setup: https://github.com/wemake-services/wemake-vue-template/blob/master/template/.gitlab-ci.yml This is almost 100% of my real setup. I have the most problems with test job:

test:
  extends: .docker
  stage: test
  script:
    - docker-compose run --rm vue npm run ci
  coverage: '/All files\s*\|\s*([\d\.]+)/'
  only:
    - merge_requests

It hangs on:

1. apk add while fetching cache:

fetch http://dl-cdn.alpinelinux.org/alpine/v3.9/main/x86_64/APKINDEX.tar.gz
fetch http://dl-cdn.alpinelinux.org/alpine/v3.9/community/x86_64/APKINDEX.tar.gz

2. npm install while fetching packages or installing packages

However, I also use several other jobs which do not hang.

Things I have tried:

1. Decrease CI timeout
2. Use verbose mode where possible
3. Restart jobs (works sometimes)
4. Restart jobs and clear runner cache (works sometimes)

Sometimes after the restart it hangs again.

At the moment CI is so unreliable it is barely usable.

Which Group/Project (with full path) is experiencing the issue?

https://gitlab.com/wemake.services

Approximate date/time when the error occurred.

3/4 days ago.

Describe what you were doing right before the issue occurred.

Nothing special. Just a regular workflow. No changed to CI / build files were made.