The consensus among marketers, experts, and documented standards is that having more than one 'envelope from' in an email message is bad practice. RFC 5321 dictates only one is allowed, and this is critical for SMTP communication. Consistency and proper authentication of the 'envelope from' are essential for email deliverability, sender reputation, and the success of SPF and DMARC checks. Multiple 'envelope from' addresses can trigger spam filters, cause unpredictable behavior in email clients, complicate bounce handling, and lead to authentication failures, ultimately harming inbox placement and brand image.