Intermittent failures cloning gitlab-org/gitlab: error reading section header 'acknowledgments'

In gitlab-development-kit!1719 (comment 466747988), @eread has been seeing intermittent failures in CI pipelines cloning gitlab-org/gitlab:

1. https://gitlab.com/gitlab-org/gitlab-development-kit/-/jobs/911520208
2. https://gitlab.com/gitlab-org/gitlab-development-kit/-/jobs/911520206
3. https://gitlab.com/gitlab-org/gitlab-development-kit/-/jobs/989235408

I've seen similar errors in my GDK when I was doing import by URL tests, so this doesn't seem like a fluke:

06:23:54.647492 pkt-line.c:80           packet:        fetch< f6669a1539d3643a47a029a17dbe2451b16a7899 refs/tags/v9.6.0.pre peeled:dd0681d772e49933b74a06812d11fff6afad81ad
06:23:54.647512 pkt-line.c:80           packet:        fetch< 0000
06:23:54.647564 pkt-line.c:80           packet:        fetch< 0002
06:23:54.697823 pkt-line.c:80           packet:        fetch> command=fetch
06:23:54.697857 pkt-line.c:80           packet:        fetch> agent=git/2.29.2
06:23:54.697862 pkt-line.c:80           packet:        fetch> object-format=sha1
06:23:54.697895 pkt-line.c:80           packet:          git< object-format=sha1
06:23:54.697912 pkt-line.c:80           packet:        fetch> 0001
06:23:54.697916 pkt-line.c:80           packet:        fetch> thin-pack
06:23:54.697920 pkt-line.c:80           packet:        fetch> no-progress
06:23:54.697923 pkt-line.c:80           packet:        fetch> ofs-delta
06:23:54.697929 pkt-line.c:80           packet:        fetch> shallow 83dcb7628f4e81ec56a9e5fc489a3a874d3f1ee2
06:23:54.697933 pkt-line.c:80           packet:        fetch> want acd5c43b66ec97d665272c859955d806ecceb5a1
06:23:54.698182 pkt-line.c:80           packet:        fetch> have 83dcb7628f4e81ec56a9e5fc489a3a874d3f1ee2
06:23:54.698186 pkt-line.c:80           packet:        fetch> 0000
06:23:54.698201 pkt-line.c:80           packet:          git< command=fetch
06:23:54.698210 pkt-line.c:80           packet:          git< agent=git/2.29.2
06:23:54.698215 pkt-line.c:80           packet:          git< 0001
06:23:54.698533 pkt-line.c:80           packet:          git< thin-pack
06:23:54.698554 pkt-line.c:80           packet:          git< no-progress
06:23:54.698559 pkt-line.c:80           packet:          git< ofs-delta
06:23:54.698565 pkt-line.c:80           packet:          git< shallow 83dcb7628f4e81ec56a9e5fc489a3a874d3f1ee2
06:23:54.698569 pkt-line.c:80           packet:          git< want acd5c43b66ec97d665272c859955d806ecceb5a1
06:23:54.698575 pkt-line.c:80           packet:          git< have 83dcb7628f4e81ec56a9e5fc489a3a874d3f1ee2
06:23:54.698579 pkt-line.c:80           packet:          git< 0000
error: RPC failed; HTTP 500 curl 22 The requested URL returned error: 500
06:24:41.064861 pkt-line.c:80           packet:          git> 0002
06:24:41.065340 pkt-line.c:80           packet:        fetch< 0002
fatal: error reading section header 'acknowledgments'

This error is coming from git-core: https://github.com/git/git/blob/eae47db8657199518b0785db6d83cf9fec179b47/fetch-pack.c#L1301-L1302. @avar @pks-t Have you seen this before?

The other failure is:

error: 4052 bytes of body are still expected
06:22:54.952551 pkt-line.c:80           packet:          git> 0002
fatal: the remote end hung up unexpectedly
fatal: early EOF
fatal: index-pack failed
warning: unable to unlink '(null)': Bad address

This looks more like an issue with connection terminating, but maybe they're the same.

Maybe more info can be seen with GIT_CURL_VERBOSE=1 rather than GIT_TRACE_PACKET=1?