CI runners hanging at the end of execution

Summary

When I configure a CI script, it runs to the end but then the execution hangs and eventually times out instead of completing.

Steps to reproduce

1. Create a CI script, even as simple as script: echo "This is a test".
2. Watch it execute and then hang instead of completing.

Expected behavior

CI scripts should complete.

Actual behavior

CI scripts hang.

Output of checks

This bug happens on GitHost hosted GitLab instance (v8.14.4).

Results of GitLab application Check

I do not know how to run these on a GitHost hosted instance.