CAS-005: CompTIA SecurityX

The sales.com message is the only entry where the sending domain (sales.com) does not match the reply-to domain (sales-mail.com), a classic header-spoofing indicator used in phishing to redirect replies to an attacker-controlled mailbox, and it is a first-time sender with no prior correspondence. Vendor.com, partner.com, and hr-saas.com all show matching sending and reply-to domains; vendor.com in particular has an established, consistent domain across two messages, so it does not fit "without previous communications," making the sales-mail.com header mismatch the pattern that should be quarantined.