On Windows Process::start creates a temporary file every time because of this code:

        if (defined('PHP_WINDOWS_VERSION_BUILD')) {
            $this->fileHandles = array(
                self::STDOUT => tmpfile(),
            );

When being invoked for thousands of times as part of task scheduling pipeline, it leaves thousands of temporary files and eventually hits the limit at 65536 files per directory, after which point it can't create a new temporary file and simply dies.

After being used, the temporary file should be deleted.