Does the 'Personal Email Detection' policy rule use the out of the box Email Address Data Identifier?
Symantec Data Loss Prevention 25.1
Personal Email Detection is a native detection rule and does not use the 'Email Address' Data Identifier. It does not reference any Data identifiers. Additional information on how this rule functions is not publicly available.
Steps on how to enable Personal Email Detection within a policy:
https://techdocs.broadcom.com/us/en/symantec-security-software/information-security/data-loss-prevention/25-1/about-data-loss-prevention-policy-authoring/about-personal-email-detection.html