Gmail and office365 gatelets do not trigger DLP violations on data found in the message body of an email.
The Gmail and office365 gatelets inspect attachments but does not inspect the message body of an email.
Feature request ISFR-2992 was created to track the request. Please contact support if you wish to be added to the feature request.
The Gsuite and Office365 seculet inspects both attachment and the message body.