Is it possible in NTA to see NetFlow traffic traversing various interfaces on a given device? We've added a number of core switches with multiple interfaces, but when we look at the top talkers all the data is coming from a single interface while I'd expect to see it received/sent on multiple interfaces. The interfaces are all configured to send NetFlow data.
If you look at the 'other' interfaces manually, can you see any netflow statistics for them? Just double check that you are indeed getting netflow statistics from all the interfaces that you are expecting to get it from.
You can do this by going into Netflow, and in Netflow Sources, click on the + next to the device you are interested in, it will then show all the interfaces that have netflow configured for them.