KEX diffie-hellman-group-exchange-sha1 isn't offered for Cisco

Hello,

I have configured almost all KEX's algorithms, see the list

    kex: [
      'ecdh-sha2-nistp256',
      'ecdh-sha2-nistp384',
      'ecdh-sha2-nistp521',
      'diffie-hellman-group-exchange-sha1',
      'diffie-hellman-group-exchange-sha256',
      'diffie-hellman-group1-sha1',
      'diffie-hellman-group14-sha1',
      'diffie-hellman-group14-sha256',
      'diffie-hellman-group15-sha512',
      'diffie-hellman-group16-sha512',
      'diffie-hellman-group17-sha512',
      'diffie-hellman-group18-sha512',
    ],

But when I'm trying to connect to Cisco then the diffie-hellman-group-exchange-sha1 is never offered and I'm not able to connect there, see

2022-11-02T16:41:15.194Z - debug: Custom crypto binding not available
2022-11-02T16:41:15.195Z - debug: Local ident: 'SSH-2.0-ssh2js1.10.0'
2022-11-02T16:41:15.195Z - debug: Client: Trying 149.196.174.121 on port 22 ...
2022-11-02T16:41:15.318Z - debug: Socket connected
2022-11-02T16:41:15.445Z - debug: Remote ident: 'SSH-2.0-Cisco-1.25'
2022-11-02T16:41:15.445Z - debug: Outbound: Sending KEXINIT
2022-11-02T16:41:15.446Z - debug: Inbound: Handshake in progress
2022-11-02T16:41:15.446Z - debug: Handshake: (local) KEX method: ecdh-sha2-nistp256,ecdh-sha2-nistp384,ecdh-sha2-nistp521,diffie-hellman-group1-sha1,diffie-hellman-group14-sha1,diffie-hellman-group14-sha256,diffie-hellman-group15-sha512,diffie-hellman-group16-sha512,diffie-hellman-group17-sha512,diffie-hellman-group18-sha512
2022-11-02T16:41:15.446Z - debug: Handshake: (remote) KEX method: diffie-hellman-group-exchange-sha1
2022-11-02T16:41:15.447Z - debug: Handshake: No matching key exchange algorithm
2022-11-02T16:41:15.447Z - debug: Outbound: Sending DISCONNECT (3)
2022-11-02T16:41:15.448Z - debug: Outbound: Sending DISCONNECT (11)
2022-11-02T16:41:15.469Z - info: Awaiting connectionEndedPromise...
2022-11-02T16:41:15.672Z - debug: Socket ended
2022-11-02T16:41:15.672Z - debug: Socket closed
2022-11-02T16:41:15.673Z - info: SocketClosedPromise finished.

But it is offered for SSH-2.0-ROSSSH - Mikrotik device

2022-11-11T08:35:24.580Z - debug: Remote ident: 'SSH-2.0-ROSSSH'
2022-11-11T08:35:24.580Z - debug: Outbound: Sending KEXINIT
2022-11-11T08:35:24.582Z - debug: Inbound: Handshake in progress
2022-11-11T08:35:24.582Z - debug: Handshake: (local) KEX method: ecdh-sha2-nistp256,ecdh-sha2-nistp384,ecdh-sha2-nistp521,diffie-hellman-group-exchange-sha1,diffie-hellman-group-exchange-sha256,diffie-hellman-group1-sha1,diffie-hellman-group14-sha1,diffie-hellman-group14-sha256,diffie-hellman-group15-sha512,diffie-hellman-group16-sha512,diffie-hellman-group17-sha512,diffie-hellman-group18-sha512
2022-11-11T08:35:24.582Z - debug: Handshake: (remote) KEX method: diffie-hellman-group-exchange-sha256,diffie-hellman-group-exchange-sha1,diffie-hellman-group14-sha1,diffie-hellman-group1-sha1
2022-11-11T08:35:24.582Z - debug: Handshake: KEX algorithm: diffie-hellman-group-exchange-sha1

So the question is why all configured algorithms are not always offered to all devices?
The last version ssh2 (1.11.0) is used

Thanks

Start with the SSH handshake's KEX negotiation, using the configured kex list and the Cisco and Mikrotik debug logs in the report as a comparison. Trace why diffie-hellman-group-exchange-sha1 is omitted for Cisco; done means the cause is established and the behavior is covered by an appropriate regression test.