Ok, the relevant binding that misses the cache is the Pants version install:

[TRACE jump::context] Installing boot binding Binding {
        target: "/root/.cache/scie/d036c571b74670fb7cccdb2ee973b51625c6419b29dd5e2e5390d6267b873904/locks/configure-b7aeeb8b50858aff30ce47276ef8773d8eb6d5815b7942c97912685abcd733e7",
        process: Process {
            env: EnvVars {
                vars: [
                    Default(
                        (
                            "PANTS_VERSION_PROMPT_SALT",
                            "",
                        ),
                    ),
                    RemoveMatching(
                        ComparableRegex(
                            PEX_.*,
                        ),
                    ),
                    Replace(
                        (
                            "PEX_PYTHON_PATH",
                            "/root/.cache/scie/cdc3a4cfddcd63b6cebdd75b14970e02d8ef0ac5be4d350e57ab5df56c19e85e/cpython-3.9.15+20221106-x86_64-unknown-linux-gnu-install_only.tar.gz/python/bin/python3.9",
                        ),
                    ),
                    Replace(
                        (
                            "PEX_ROOT",
                            "/root/.cache/scie/d036c571b74670fb7cccdb2ee973b51625c6419b29dd5e2e5390d6267b873904/bindings/pex_root",
                        ),
                    ),
                ],
            },
            exe: "/root/.cache/scie/cdc3a4cfddcd63b6cebdd75b14970e02d8ef0ac5be4d350e57ab5df56c19e85e/cpython-3.9.15+20221106-x86_64-unknown-linux-gnu-install_only.tar.gz/python/bin/python3.9",
            args: [
                "/root/.cache/scie/04c117900eb9bf6005a70e25aa2dfe83ac94d648920c65b356c79cf8efdf48dc/tools.pex",
                "configure-pants",
                "--ptex-path",
                "/root/.cache/scie/fd8ceac7b3026655b34b2c80997c18caeb7e8d64a9dd08c0340a5ced92f947d3/ptex",
                "--pants-version",
                "2.15.0",
                "--pants-sha",
                "",
                "--pants-config",
                "/codebuild/output/src246925278/src/pants.toml",
                "--github-api-bearer-token",
                "",
                "/root/.cache/scie/d036c571b74670fb7cccdb2ee973b51625c6419b29dd5e2e5390d6267b873904/bindings",
            ],
        },
    }
[DEBUG jump::atomic] The atomic file at /root/.cache/scie/fd8ceac7b3026655b34b2c80997c18caeb7e8d64a9dd08c0340a5ced92f947d3/ptex has already been established.
[DEBUG TimerFinished] installer::unpack_blob(), Elapsed=8.882µs
[DEBUG jump::atomic] The atomic file at /root/.cache/scie/04c117900eb9bf6005a70e25aa2dfe83ac94d648920c65b356c79cf8efdf48dc/tools.pex has already been established.
[DEBUG TimerFinished] installer::unpack_blob(), Elapsed=11.613µs
[DEBUG jump::atomic] The atomic directory at /root/.cache/scie/cdc3a4cfddcd63b6cebdd75b14970e02d8ef0ac5be4d350e57ab5df56c19e85e/cpython-3.9.15+20221106-x86_64-unknown-linux-gnu-install_only.tar.gz has already been established.
[DEBUG TimerFinished] installer::unpack_archive(), Elapsed=4.846µs
[DEBUG TimerFinished] Installer::install(), Elapsed=32.059µs
Failed to fetch <https://binaries.pantsbuild.org/tags/pantsbuild.pants/release_2.15.0>: [28] Timeout was reached (Failed to connect to <http://binaries.pantsbuild.org|binaries.pantsbuild.org> port 443 after 257769 ms: Couldn't connect to server)