Throughput test issues related to git metadata repo

Occasionally the throughput tests show a 50% drop because one job failed like so:

# Adding key db0aa474 to git repository at /scratch/z5/lhcbpr/jenkins/workspace/nightly-builds/tests/output/lhcb-metainfo/.git
Traceback (most recent call last):
  File "/scratch/z5/lhcbpr/jenkins/workspace/nightly-builds/tests/build/Gaudi/InstallArea/x86_64_v3-centos7-gcc11-opt+g/bin/gaudirun.py", line 584, in <module>
    exec(o, g, l)
  File "<string>", line 1, in <module>
  File "/scratch/z5/lhcbpr/jenkins/workspace/nightly-builds/tests/build/Gaudi/InstallArea/x86_64_v3-centos7-gcc11-opt+g/bin/gaudirun.py", line 543, in __call__
    importOptions(arg)
  File "/scratch/z5/lhcbpr/jenkins/workspace/nightly-builds/tests/build/Gaudi/InstallArea/x86_64_v3-centos7-gcc11-opt+g/python/GaudiKernel/ProcessJobOptions.py", line 552, in importOptions
    _import_function_mapping[ext](optsfile)
  File "/scratch/z5/lhcbpr/jenkins/workspace/nightly-builds/tests/build/Gaudi/InstallArea/x86_64_v3-centos7-gcc11-opt+g/python/GaudiKernel/ProcessJobOptions.py", line 486, in _import_python
    exec(code, {})
  File "/scratch/z5/lhcbpr/jenkins/workspace/nightly-builds/tests/build/Moore/Hlt/Hlt1Conf/options/hlt1_pp_default.py", line 15, in <module>
    run_moore(options, all_lines)
  File "/scratch/z5/lhcbpr/jenkins/workspace/nightly-builds/tests/build/Moore/InstallArea/x86_64_v3-centos7-gcc11-opt+g/python/Moore/config.py", line 680, in run_moore
    configure(
  File "/scratch/z5/lhcbpr/jenkins/workspace/nightly-builds/tests/build/LHCb/InstallArea/x86_64_v3-centos7-gcc11-opt+g/python/PyConf/application.py", line 1021, in configure
    if options.write_decoding_keys_to_git: key_registry.flush_to_git()
  File "/scratch/z5/lhcbpr/jenkins/workspace/nightly-builds/tests/build/LHCb/InstallArea/x86_64_v3-centos7-gcc11-opt+g/python/PyConf/filecontent_metadata.py", line 191, in flush_to_git
    _flush_keys_to_git(
  File "/scratch/z5/lhcbpr/jenkins/workspace/nightly-builds/tests/build/LHCb/InstallArea/x86_64_v3-centos7-gcc11-opt+g/python/PyConf/filecontent_metadata.py", line 101, in _flush_keys_to_git
    _commit_oid_to_branch(path, 'master', branch_name, oid)
  File "/scratch/z5/lhcbpr/jenkins/workspace/nightly-builds/tests/build/LHCb/InstallArea/x86_64_v3-centos7-gcc11-opt+g/python/PyConf/filecontent_metadata.py", line 301, in _commit_oid_to_branch
    commit = _get_commit_for_branch(path, parent)
  File "/scratch/z5/lhcbpr/jenkins/workspace/nightly-builds/tests/build/LHCb/InstallArea/x86_64_v3-centos7-gcc11-opt+g/python/PyConf/filecontent_metadata.py", line 282, in _get_commit_for_branch
    assert len(sha1) == 40, 'expect valid SHA1 - got {}'.format(sha1)
AssertionError: expect valid SHA1 - got 

The corresponding test output is here and the logs are attached as tests.log