Oddly, it turns out it's the "--junit-xml" parameter during buildbot tests that is making it reproducible there.
Pass: python_d -m test.regrtest test_ssl
Fail: python_d -m test.regrtest --junit-xml out.xml test_ssl
The latter consistently fails all of the time for me manually.
I also found what I think is the same commit Pablo just referenced (albeit the cherry pick version on the 3.10 branch) - ea47a8a71ad56ec349f02bf8c6a1d3bf04acabcc. Reverting just that commit as part of the latest 3.10 source passes.