DLP - Unique matches

We are setting up a DLP policy to detect a unique match for some keywords using a regex expression. The problem we are facing is that duplicate results only count as 1 unique result - even with the instance count set to 3. The MS docs don't really explain how unique/duplicate results are handled and I could only find an old tech community question that references a new feature update from 2017. https://techcommunity.microsoft.com/t5/security-compliance-and-identity/new-quot-customizing-dlp-quot-feature-mc111748-where-is-it/m-p/92795

Is there any official document that explains this scenario a bit better?