download stuck. works with vuze

[uzer]

hi,
a hand full of my downloads are stuck, all between 70% and 90% (various trackers). Seeder are available, usually more than one. they're all connectable and are seeding the full file (100%). I also did manual rechecks, but no success. after checking them the files continued not downloading at 70-90%
so I tested a torrent with vuze (aka azureus). it checked the incomplete deluge-downloaded stuff and started downloading at a nice rate. so it's not the file and not the seeders. also, a torrent that didn't go above 10kb/s in deluge started downloading with constant 40kb/s in azureus.
no, and I did not have any download restictions. neither download limit nor number of active downloads.
this happened with both, deluge 1.1.9 and 1.2.0. the torrents that are stuck seem to be totally random. torrents from the same tracker with the same preferences work flawless.

I've been using deluge for quite some time now and I really like it. but if there's no solution to the problem described i think i need to switch over, until it is.

i'm on ubuntu karmic by the way
if you need more info, i'll post it

thanks in advance

[loki]

I've had this happen occasionally too, is there any blocklist you have enabled in Deluge?