NCM - 10.1.x
NCM supports below MAC algorithms for device connections via Terminal.
NCM has local putty, which is used for Terminal connections to devices during discovery/pull/push operations.
As per putty code there is no support for hmac-sha2-512 whereas they do support hmac-sha2-256, hence the same is the case in NCM.
Refer PuTTY wish hmac-sha2-512 for details.
If SHA2 is preferred in user environment, configure the device with hmac-sha2-256, for NCM to discover/pull/push configuration of device via CLI.