Inside source3/client/client.c:browse_host() we have:

4913         if (browse_host_rpc(sort)) {
4914                 return true;
4915         }
4916 
4917         if (lp_client_min_protocol() > PROTOCOL_NT1) {
4918                 return false;
4919         }
4920 
4921         ret = cli_RNetShareEnum(cli, browse_fn, NULL);

which depends on the administrator or user of smbclient setting the 'client min protocol' correctly when talking to an SMB2-only server.

We already have the protocol information on the server we connected to inside cli->conn, so we need to prevent calling the SMB1-only cli_RNetShareEnum() when connected to an SMB2-only server.

libsmbclient already protects against this, so we just missed this in smbclient. We just need to add a:

        if (smbXcli_conn_protocol(conn) > PROTOCOL_NT1) {
                return false;
        }

check before the cli_RNetShareEnum() call to fix this in the same way as it was
fixed for libsmbclient.

I'll upload a patch shortly.