Any detector assigned to a policy group will attempt to load any/all policies assigned to it.
Release : 15.x.x / 16.x.x
Component : Any
Its considered best practice to separate policy groups based on detection types. If you have a policy group assigned to both Email and WSS/CASB detectors, then the policy and response rules will get assigned to both. Since most response rules should only be assigned to specific detector types, it will have issues handling the response rules, which can impact policies/performance.
Create a policy group only for CASB data-at-rest policies, and assign it only to the CASB detector. Do this for WSS, Email, and endpoint as well.