derick has already merged the pull request for this to timelib (https://github.com/derickr/timelib/commit/deced3e1f875fa460a7c074e558c7b587b765287), however mongoDB hasn't updated its version of timelib to pick up these changes. This ticket should include updating/integrating the latest version of timelib after SERVER-32771 and adding support for the format specifier '%L' to indicate milliseconds.