Text of autoresponder was changed for domain in Plesk, but old autoreply is still sent.
MailEnable auto-responder is enabled instead of Plesk. Due to that MailEnable auto-response is received instead of Plesk.
Disable the auto-responder function in MailEnable:
MailEnable Management > Messaging Manager > Post office > Domain name > Mailboxes > Mailbox Properties > Actions .