I can see all the network activity going on on my PC.

The Network monitor shows that Fopnu is constantly downloading at around 20KB/s while there aren’t any downloads
taking place. I don’t think that’s normal, if it is , then please explain why..

If you are in any channels that is where the bandwidth is coming from.

Also wanted to mention that all the channels are offline, incase someone would ask if i have active channels .

Can someone tell me if their Fopnu client is also consuming dl bandwidth without active downloads or channels?

That is just network bandwidth. It is normal to have some even when you are doing nothing else. Also if you have files shared you could be found in a search, and that's bandwidth.