I'm testing field extractions on some new logs. I created simple regex to extract server names from the logs, and used REPORTS in transforms. The field extraction is not working at search time. validated with rex.
IN addition, your rex command is trying to capture a space, while your extraction is not trying to capture a space. I'm not sure if you want one or not. If you do, that would probably be REGEX = \s([a-z][a-z]-[a-z][a-z][a-z][0-9][0-9])