Winston rotate writing to mutiple files

So Im using winston-daily-rotate-file. In app.js I have:

var logger = require('./logger');

and then:

logger.info("logging to info");
logger.error("logging to error");

In logger/index.js I have:

var error_transport = new winston.transports.DailyRotateFile({
    filename: '../logs/error',
    datePattern: 'yyyy-MM-dd.',
    prepend: true,
    level: 'error',
name: 'error'
});
var info_transport = new winston.transports.DailyRotateFile({
    filename: '../logs/info',
    datePattern: 'yyyy-MM-dd.',
    prepend: true,
    level: 'info',
    name: 'info'
});

var logger = new (winston.Logger)({
    transports: [
        error_transport,
        info_transport
    ]
});

module.exports = logger;

What happens is that the file

logs/DATE_error

contains:

logging to error    

BUT: the file

logs/DATE_info 

contains:

logging to info
logging to error

Why is the info file also including logs from error?

via oderfla