Yes unfortunately the doc on this system is scarce, so the source code is often the best option.
The AI debugging tools can also be very helpful to find what’s happening in a visual way:
https://dev.epicgames.com/documentation/en-us/unreal-engine/ai-debugging-in-unreal-engine
And the visual logger can give you a lot of valuable information on the state of the perception component for each of your ai controller:
https://dev.epicgames.com/documentation/en-us/unreal-engine/unreal-insights-in-unreal-engine?application_version=5.3