Sensitive content does not get monitored on IE 11,
Firefox, Edge Chromium, and Chrome for the following
Known issue DLP-36661
Release : 15.5, 15.7, 15.8
Component : DLP Agent print monitoring
This has been resolved for DLP 16.0.
15.7 MP2 HF 15.7.00207.01003 resolves this issue.
Engineering is working on a fix for 15.8 MP1, there is no ETA as of this date (5 Aug 2021).