The device name is polled during the discovery process only, not during a regular polling period. If you change the name of a device after it has been discovered in the Gateway, the new name will not appear in the device list automatically.
In Gateway versions 1.8.1 and later, click the Retrieve details link at the top of the details page to update the device name. In previous Gateway versions, rediscover the device to update its name.
In general, static values for device attributes are only polled at discovery, for example, the items on the device details page. Sensor measurements are polled during the regular polling period.