git checkout fails in scallywag

[Andrew Schulman]

In my latest push of fish to scallywag
(https://github.com/cygwin/scallywag/actions/runs/34336457868/job/102416876538#annotation:26:16),
the build fails in the source step. There's no build log that I can see, but
at the top of the page under Annotations, it says:

Post Run action/checkout@v7
The process 'D:\cygwin\bin\git.exe' failed with exit code 128

Can you advise? Something I'm doing wrong?

Thanks,
Andrew