I had to return back to 6.60 beta 3, because beta 5 stopped downloading multiple times. Closing and restarting of Newsbin is needed when it stops downloading. Nothing else helps.
Quite possibly the problem is related to specific corrupt headers, though:
This situation occurs after numerous "no such article" messages, and I have somewhat corrupt headers in some groups, it seems.
Some time ago I scanned the same headers from a different server when they were already present, and for some reason I have posts duplicated in the group pane, instead of merged together.
It seems that those posts now expired on one of the servers.
So here what happens:
6.60 beta 5: after multiple "no such article" messages Newsbin simply stops downloading anything, even other correct posts. Downloading is possible in small increments by restarting Newsbin multiple times.
6.60 beta 3: duplicate files are downloaded, one copy is OK, the other copy is incomplete (I was using bypass filters option). Multiple "no such article" messages are also occurring , but they do not cause NewsBin to stop downloading.