Cannot download torrents to nullfs any more

[emanruse]

Some trackers require a minimum download traffic for a certain time.

So far I have always been able to download torrents to nullfs. I have used qBittorrent or Deluge to do this. Strangely recently I am no longer able to do this. What happens:

The torrent client starts downloading, gets about 10-15Mb of data and shows an error message about the local file.

I tried recompiling nullfs, thinking that it might have become incompatible with newer system libs. Unfortunately, that didn't help and the issue remains.

What could be the reason? How come so far this worked but not any more?