SSH connection problem, why is the user being substituted?

Question

SSH

Hello.
On another poppy and in bash under Windows, this key works with this command.
ssh changes user ubuntu to slider for some reason. There is no slider user in the system at all.

[email protected]:~/.keys$ ssh -i ./oltr.pem -l ubuntu ec2-18-215-187-173.compute-1.amazonaws.com  -vvv
OpenSSH_7.9p1, LibreSSL 2.7.3
debug1: Reading configuration data /Users/oleg/.ssh/config
debug1: /Users/oleg/.ssh/config line 1: Applying options for *
debug1: Reading configuration data /etc/ssh/ssh_config
debug1: /etc/ssh/ssh_config line 48: Applying options for *
debug1: Connecting to ec2-18-215-187-173.compute-1.amazonaws.com port 22.
debug1: Connection established.
debug1: identity file ./oltr.pem type -1
debug1: identity file ./oltr.pem-cert type -1
debug1: Local version string SSH-2.0-OpenSSH_7.9
debug1: Remote protocol version 2.0, remote software version OpenSSH_7.2p2 Ubuntu-4ubuntu2.8
debug1: match: OpenSSH_7.2p2 Ubuntu-4ubuntu2.8 pat OpenSSH_7.0*,OpenSSH_7.1*,OpenSSH_7.2*,OpenSSH_7.3*,OpenSSH_7.4*,OpenSSH_7.5*,OpenSSH_7.6*,OpenSSH_7.7* compat 0x04000002
debug3: fd 4 is O_NONBLOCK
debug1: Authenticating to ec2-18-215-187-173.compute-1.amazonaws.com:22 as 'slider'
debug3: hostkeys_foreach: reading file "/Users/oleg/.ssh/known_hosts"
debug3: record_hostkey: found key type ECDSA in file /Users/oleg/.ssh/known_hosts:20
debug3: load_hostkeys: loaded 1 keys from ec2-18-215-187-173.compute-1.amazonaws.com
debug3: order_hostkeyalgs: prefer hostkeyalgs: [email protected],[email protected],[email protected],ecdsa-sha2-nistp256,ecdsa-sha2-nistp384,ecdsa-sha2-nistp521
debug3: send packet: type 20
debug1: SSH2_MSG_KEXINIT sent
debug3: receive packet: type 20
debug1: SSH2_MSG_KEXINIT received
debug2: local client KEXINIT proposal
debug2: KEX algorithms: curve25519-sha256,[email protected],ecdh-sha2-nistp256,ecdh-sha2-nistp384,ecdh-sha2-nistp521,diffie-hellman-group-exchange-sha256,diffie-hellman-group16-sha512,diffie-hellman-group18-sha512,diffie-hellman-group14-sha256,diffie-hellman-group14-sha1,ext-info-c
debug2: host key algorithms: [email protected],[email protected],[email protected],ecdsa-sha2-nistp256,ecdsa-sha2-nistp384,ecdsa-sha2-nistp521,[email protected],[email protected],[email protected],[email protected],ssh-ed25519,rsa-sha2-512,rsa-sha2-256,ssh-rsa
debug2: ciphers ctos: [email protected],aes128-ctr,aes192-ctr,aes256-ctr,[email protected],[email protected]
debug2: ciphers stoc: [email protected],aes128-ctr,aes192-ctr,aes256-ctr,[email protected],[email protected]
debug2: MACs ctos: [email protected],[email protected],[email protected],[email protected],[email protected],[email protected],[email protected],hmac-sha2-256,hmac-sha2-512,hmac-sha1
debug2: MACs stoc: [email protected],[email protected],[email protected],[email protected],[email protected],[email protected],[email protected],hmac-sha2-256,hmac-sha2-512,hmac-sha1
debug2: compression ctos: none,[email protected],zlib
debug2: compression stoc: none,[email protected],zlib
debug2: languages ctos: 
debug2: languages stoc: 
debug2: first_kex_follows 0 
debug2: reserved 0 
debug2: peer server KEXINIT proposal
debug2: KEX algorithms: [email protected],ecdh-sha2-nistp256,ecdh-sha2-nistp384,ecdh-sha2-nistp521,diffie-hellman-group-exchange-sha256,diffie-hellman-group14-sha1
debug2: host key algorithms: ssh-rsa,rsa-sha2-512,rsa-sha2-256,ecdsa-sha2-nistp256,ssh-ed25519
debug2: ciphers ctos: [email protected],aes128-ctr,aes192-ctr,aes256-ctr,[email protected],[email protected]
debug2: ciphers stoc: [email protected],aes128-ctr,aes192-ctr,aes256-ctr,[email protected],[email protected]
debug2: MACs ctos: [email protected],[email protected],[email protected],[email protected],[email protected],[email protected],[email protected],hmac-sha2-256,hmac-sha2-512,hmac-sha1
debug2: MACs stoc: [email protected],[email protected],[email protected],[email protected],[email protected],[email protected],[email protected],hmac-sha2-256,hmac-sha2-512,hmac-sha1
debug2: compression ctos: none,[email protected]
debug2: compression stoc: none,[email protected]
debug2: languages ctos: 
debug2: languages stoc: 
debug2: first_kex_follows 0 
debug2: reserved 0 
debug1: kex: algorithm: [email protected]
debug1: kex: host key algorithm: ecdsa-sha2-nistp256
debug1: kex: server->client cipher: [email protected] MAC: <implicit> compression: none
debug1: kex: client->server cipher: [email protected] MAC: <implicit> compression: none
debug3: send packet: type 30
debug1: expecting SSH2_MSG_KEX_ECDH_REPLY
debug3: receive packet: type 31
debug1: Server host key: ecdsa-sha2-nistp256 SHA256:GmV1XDy/7JguDcpRtw8WkqHnGt/Wg4zjSJUKtuaflq0
debug3: hostkeys_foreach: reading file "/Users/oleg/.ssh/known_hosts"
debug3: record_hostkey: found key type ECDSA in file /Users/oleg/.ssh/known_hosts:20
debug3: load_hostkeys: loaded 1 keys from ec2-18-215-187-173.compute-1.amazonaws.com
debug3: hostkeys_foreach: reading file "/Users/oleg/.ssh/known_hosts"
debug3: record_hostkey: found key type ECDSA in file /Users/oleg/.ssh/known_hosts:20
debug3: load_hostkeys: loaded 1 keys from 18.215.187.173
debug1: Host 'ec2-18-215-187-173.compute-1.amazonaws.com' is known and matches the ECDSA host key.
debug1: Found key in /Users/oleg/.ssh/known_hosts:20
debug3: send packet: type 21
debug2: set_newkeys: mode 1
debug1: rekey after 134217728 blocks
debug1: SSH2_MSG_NEWKEYS sent
debug1: expecting SSH2_MSG_NEWKEYS
debug3: receive packet: type 21
debug1: SSH2_MSG_NEWKEYS received
debug2: set_newkeys: mode 0
debug1: rekey after 134217728 blocks
debug1: Will attempt key: ./oltr.pem  explicit
debug2: pubkey_prepare: done
debug3: send packet: type 5
debug3: receive packet: type 7
debug1: SSH2_MSG_EXT_INFO received
debug1: kex_input_ext_info: server-sig-algs=<rsa-sha2-256,rsa-sha2-512>
debug3: receive packet: type 6
debug2: service_accept: ssh-userauth
debug1: SSH2_MSG_SERVICE_ACCEPT received
debug3: send packet: type 50
debug3: receive packet: type 51
debug1: Authentications that can continue: publickey
debug3: start over, passed a different list publickey
debug3: preferred publickey,keyboard-interactive,password
debug3: authmethod_lookup publickey
debug3: remaining preferred: keyboard-interactive,password
debug3: authmethod_is_enabled publickey
debug1: Next authentication method: publickey
debug1: Trying private key: ./oltr.pem
debug3: sign_and_send_pubkey: RSA SHA256:TjCWLJZ3D4iO4Unx2PHhFePkv8N5JHWudS3WvWoR1yc
debug3: sign_and_send_pubkey: signing using rsa-sha2-512
debug3: send packet: type 50
debug2: we sent a publickey packet, wait for reply
debug3: receive packet: type 51
debug1: Authentications that can continue: publickey
debug2: we did not send a packet, disable method
debug1: No more authentication methods to try.
[email protected]: Permission denied (publickey).
[email protected]:~/.keys$

The user also changes when connected to a neighboring computer in the home grid

[email protected]:~/.keys$ ssh [email protected]
[email protected]'s password:

[email protected]:~/.keys$ which ssh
/usr/bin/ssh
[email protected]:~/.keys$ ls /usr/bin/ssh
-rwxr-xr-x  1 root  wheel  2099264 May  4 10:49 /usr/bin/ssh