Symantec Data Loss Prevention (DLP) Indexed Policy Matching (IDM) policies are not working for partial data matches. Those policies will work with exact data matches. The incidents will show either "exact" or "100%". The incidents show "exact" if there is an exact match. They show "100%" if there is a partial match.
DLP 14.6 MP2
Per the Admin Guide, the minimum number of normalized characters for exact matching is 50. Whereas, the minimum number of normalized characters for partial matching is 300. The test files being used were a little over 50 characters after normalization.