You are using a Social Security Number (SSN) or Credit Card Number (CCN) narrow breadth policy on Symantec Data Loss Prevention (DLP), and have added your own list of keyword validators to the policy, but they do not seem to be working.
The narrow breadth Data Identifiers all have built-in validators that cannot be changed. In the case of keyword validators, that list is fixed. The Data Identifier keywords are evaluated before the optional validators. As a result, new keywords cannot be added to a Data Identifier with predefined values. The optional validator list can be used to reduce the number of keywords, not increase.
There are two possible courses of action: