Email notification - email is missing Message-ID header

Steps to reproduce:

1. Zabbix server version 6.0.9

Result:
Email notification sent does not have Message-ID header field.

This rated negative by SPAM detection.
Do all emails have Message-ID?
 
According to RFC 2822, each email should have a globally-unique identifier to distinguish it from other emails.

Expected:

Create emails with Message-ID header field.