User violating a policy is being notified by email about the violation, even though the policies responses Notify User is unchecked.
Using the Policy Template: PCI Violation Detection for Content for a Data Exposure Policy will automatically set Notify User as a response and this cannot be turned off.
Recreate PCI policy with the same rules, but do not use the Template Policy for PCI violation. The policy should no longer notify the violator with an email.