For a long time, noticed the also problem with alt-binz's par function.
Especially, when there is a long list of separate files, that are batch downloaded, the par list ... looks like it "stalls". In reality, it will check / join / repair the files, but slowly, very slowly. May take hour and hours just to do a few GB.
Not only that, because it takes so long, alt-binz "forgets" to query/download the other par2 repair files.
A easy way to sometimes see this effect is: search for "720p horriblesubs". Select like the last 15 days from one poster like Ishouni ( to keep consistent ) on BinSearch ( probably around 10 to 15GB ), and then place them all in query. Download will go good. You see a 20 or 30 files in the par2 tab. No problems. But as it downloads the files, the 001,002,003,004 files just pile up ( especially on a fast connection ), while the par2 check, is slow as hell. And this then trigger possible problems later ( not downloading "spare par2 files" for repairs ) etc...
Its almost like having too many different par2 sets in the same download directory triggers this problem. Almost like par2 check does not check on the title, but all the par2 files in the directory. So for each file its checking, it opens "all" the par2 files, to see what belongs to "episode 1". Then it does the same for "episode 2". And ...
Splitting the exact same files, one by one ( major job ), and everything is perfect. Feels like the par2 check / repair is greedy.
Interesting problem also. I can always tell that there is something wrong with the par2 repair/check, when you select 1 or more items, and you can not delete them from the par2 tab ( unless you close alt-bins, wait for it to finish, open alt-binz, and if your list is still there, you can delete items with ease ).