Netflow Plug-in Data issues

We are noticing that information in the devices tab is not all there. What's confusing to me is that I'm getting 1 min - 24 hour traffic graphs, but anything beyond that is showing as blank. Is it old stale data for the 1 min to 24 hour? or is there a process that's not compiling the data post 24 hours?

For example (attachments included):

When I go to the device, in the traffic tab I pick last month report the data seems to stop around March 3rd. However if I stay in traffic on the same device and choose last 6 hours instead of last month - I get a graph of one minute averages. Same with 24 hours. But anything beyond 24 hours the graphs will be blank. Very confused. I'm taking over the management of this box, learning as I go.

I also am noticing 0 information in the graphs in the conversation tab.

Thanks.