Same thing happened to my PRs. If it is any consolation after 10 hours mine kicked into life. Run the CI build commands locally and
if you are happy you can merge the PR without waiting for the build to complete. That's just what I do, I'm not suggesting this will work for everyone.
The real answer must be to fix the Jenkins Infra CI environment to be more stable / provide better feedback to the PR on these types of errors. But that will take time.