A model or type UNKNOWN indicates the host or lim on the host is down. You need to take immediate action.
If automatic detection of host type or model fails, and the host type configured in ego.shared cannot be found, then Matched Type gets set to DEFAULT. A Matched Type reported as DEFAULT may contribute to binary incompatibilities; a Matched Model reported as DEFAULT may be inefficient due to an incorrect CPU factor. You can run lim -t to detect the real type or model for a host, and then make changes to ego.shared.