I believe this is a bug.
Just pushed a commit to GitHub. This triggered a PR branch build on CI, but it fails with an error that it can’t find the commit:
Warning: Permanently added 'github.com,188.8.131.52' (RSA) to the list of known hosts. fatal: Could not parse object 'ac1d28d8e598ca3ea9c78e35db32af206b653603'. Could not find commit ac1d28d8e598ca3ea9c78e35db32af206b653603 in the repo
Maybe I have something configured wrong?