Is there any known issue with materializing snapshots and process execution against those snapshots hitting races? I see:

Computing ExecuteProcess(ExecuteProcessRequest { argv: ["./pex37", "--python", "/home/jsirois/dev/pantsbuild/jsirois-pants/build-support/pants_dev_deps.py37.venv/bin/python", "-e", "pytest:main", "-o", "pytest-with-requirements.pex", "more-itertools<6.0.0 ; python_version<\'3\'", "pytest>=3.0.7,<3.7", "pytest-timeout>=1.2,<1.3", "pytest-cov>=2.4,<2.5", "unittest2>=0.6.0,<=1.9.0"], env: {"PATH": "/home/jsirois/dev/pantsbuild/jsirois-pants/build-support/pants_dev_deps.py37.venv/bin"}, input_files: Digest(Fingerprint<5fa481ff5a27d9e27f822a03f5e7168d91477eaf2228c38735217163de742e49>, 83), output_files: {"pytest-with-requirements.pex"}, output_directories: {}, timeout: 900s, description: "Resolve requirements for testprojects/tests/python/pants/dummies:failing_target", jdk_home: None }
                     E   +             Throw(Failed to execute process: Error launching process: Os { code: 26, kind: Other, message: "Text file busy" })
                     E   +

Which implies

./pex37

is mutating when also being used as an executable IIUC.