It looks like starting in 13.12.0-pre 25ab40a4d61 unit Tests are not working as they did before.
Before you could access tests from the pipeline even when other jobs were still running.
Now when you access https://gitlab.com/:id/-/pipelines/:id/test_report it will only display There are no test reports for this pipeline You can configure your job to use unit test reports, and GitLab displays a report here and in the related merge request. even if it shows tests exist in the tab.
This looks like a regression related to a recent change, we’ll take a look. Do the test results replace this message once the pipeline is done running?