The reason this happens is that AIS name messages were added to the NMEA2000 specification relatively recently (2010) as it took some time for the NMEA standards organisation to define the message structure. Prior to this, individual manufacturers (Simrad / Garmin / Raymarine etc) adopted their own proprietary messages for Class B vessel names on an NMEA2000 network. This meant that their own AIS equipment could communicate with their own displays, but created compatibility problems between manufacturers.