hi rgward,
this is something that should be fixed in NPM 10.6 RC.
@johndpeeknd - I appreciate your feedback. We have developed this feature for users that intensively use multicast data and they are satisfied with this V1 - mainly because of multicast group and multicast topology information. The use case here is to focus on groups and mutlicast routers in your network. It won't tell you who inside the subnet that's subscribed to the multicast group having the issues - client/end station. But typically, if there is an issue, it's caused by problem in whole network segment not just a single client (but I agree that this would be very nice to have there).
If you can describe what exactly you are trying to solve I'd would be happy to include this into multicast future enhancements.