![](https://lemmy.blackeco.com/pictrs/image/89918557-ee82-4674-8c6d-89a9ee060057.jpeg)
![](https://lemmy.world/pictrs/image/0da8d285-3457-4e5b-af21-b38609b07eea.webp)
If you watch the PRs history, you can see that the user github-actions
edited them. This user is the default one when a GitHub Action (the pipeline OP refers to) alters the repo. So someone probably submitted a pull request abusing the GitHub token when the Action ran on their PR.
Most likely someone submitted a pull request that abused the GitHub token of the Action running on new PRs in order to edit all the other pull requests.