Version:           4.3.2 (using 4.3.2 (KDE 4.3.2), Mandriva Linux release 2010.0 (Cooker) for x86_64)
Compiler:          gcc
OS:                Linux (x86_64) release 2.6.31.5-1mnbX

if you have subscribed to more than 100 groups knode will fail to retrieve articles when the "Get New Articles in all Groups" button is clicked, or if the "Timed Interval Update"  feature is used.
The failure is that at around 100 groups the retrieval stops and goes into wait mode forever or until you click on Stop Network. Any groups over 100 are not updated. 
You can still click on the individual group and update it tho.
I also noted that the download is opening many threads (see lower right expanded download indicator in the knode gui) but only using a few of them (about 4), the rest are in permanent wait mode and never do any work.
Another issue is that it is impossible to right click on a group and unsubscribe. Right-clicking a group activates an update and download of the its articles preventing unsubscribing.