CI failure in SHA256 Git fork: fatal: mismatched algorithms: client sha1; server sha256

Hi! I get the following error directly when running a pipeline in a fork of Git SHA256 project, after making the first commit:

https://gitlab.com/debdistutils/tacos/build-containers/-/jobs/12588541074

Running with gitlab-runner 18.7.0~pre.433.g3a5f2314 (3a5f2314)
  on blue-3.saas-linux-medium-amd64.runners-manager.gitlab.com/default U4xQPDyhm, system ID: s_b59597d5b921
Resolving secrets
Preparing the "docker+machine" executor 00:08
Using Docker executor with image debian:trixie-slim ...
Using effective pull policy of [always] for container debian:trixie-slim
Pulling docker image debian:trixie-slim ...
Using docker image sha256:ec14a04444fe3ea67a9027638691cf91fb16cd8bda8b35907101578348e05789 for debian:trixie-slim with digest debian@sha256:4bcb9db66237237d03b55b969271728dd3d955eaaa254b9db8a3db94550b1885 ...
Preparing environment 00:01
Using effective pull policy of [always] for container sha256:64d8b25f54a0bc4b2934db822e0c95e352590e981deb83b625e1aea0dbfc2c9e
Running on runner-u4xqpdyhm-project-77433570-concurrent-0 via runner-u4xqpdyhm-s-l-m-amd64-1767351214-c83e340b...
Getting source from Git repository 00:01
Gitaly correlation ID: 5fc58aa3ec9740629d8c4d919d5f92de
Fetching changes with git depth set to 20...
Initialized empty Git repository in /builds/debdistutils/tacos/build-containers/.git/
Created fresh repository.
fatal: mismatched algorithms: client sha1; server sha256
Cleaning up project directory and file based variables 00:01
ERROR: Job failed: exit code 1

This appears similar to #510968 (closed) but that was resolved, and I can confirm that pipelines in the original (non-fork) works fine:

https://gitlab.com/debdistutils/build/stage-n-container/-/jobs/12588587902

So this is not the same issue, but one that only happens in a fork of a Git SHA256 project.

It seems like that the SHA256 setting is lost when making a fork of a project, at least from the perspective of runners.

Any ideas?

Thanks, Simon