Comment 6 for bug 1021632

I can confirm this on qBittorrent 3.1.9.2 with Win7. I remove trackers, close qBittorrent, start it again and all the trackers are back.

Libtorrent 0.16.16.0
Boost 1.55.0

If you want to test with the specific torrent I used to reproduce this you can use the torrent of the Windows version of LibreOffice 4.2.2.

Link to torrent file: http://download.documentfoundation.org/libreoffice/stable/4.2.3/win/x86/LibreOffice_4.2.3_Win_x86.msi.torrent
Magnet link: magnet:?xt=urn:btih:VMPXWKXSFL43YGJFNVXXAJVRX7HM4OE2&dn=LibreOffice_4.2.3_Win_x86.msi&tr=http%3a%2f%2ftracker.documentfoundation.org%3a6969%2fannounce

Log doesn't show anything unusual:

01/05/2014 19:57:36 - External IP: [REDACTED]
01/05/2014 19:57:36 - qBittorrent is successfully listening on interface :: port: TCP/6881
01/05/2014 19:57:36 - qBittorrent is successfully listening on interface 0.0.0.0 port: TCP/6881
01/05/2014 19:57:36 - 'C:\Users\veikk0\AppData\Local\qBittorrent\BT_backup\824ac5215ef7e551e6acc993cf499f301b9a40fa.torrent' resumed. (fast resume)
01/05/2014 19:57:36 - 'C:\Users\veikk0\AppData\Local\qBittorrent\BT_backup\ab1f7b2af22af9bc19256d6f7026b1bfcece389a.torrent' resumed. (fast resume)
01/05/2014 19:57:36 - 'C:\Users\veikk0\AppData\Local\qBittorrent\BT_backup\16c031b31524ce9df0c1db6e4eb511a94b014ba8.torrent' resumed. (fast resume)
01/05/2014 19:57:35 - Options were saved successfully.
01/05/2014 19:57:35 - Embedded Tracker [OFF]
01/05/2014 19:57:35 - Encryption support [ON]
01/05/2014 19:57:35 - Local Peer Discovery support [ON]
01/05/2014 19:57:35 - PeX support [ON]
01/05/2014 19:57:35 - DHT support [ON], port: UDP/6881
01/05/2014 19:57:35 - Anonymous mode [OFF]
01/05/2014 19:57:35 - HTTP user agent is qBittorrent v3.1.9.2
01/05/2014 19:57:35 - UPnP / NAT-PMP support [OFF]
01/05/2014 19:57:35 - qBittorrent is trying to listen on any interface port: TCP/6881
01/05/2014 19:57:35 - Peer ID: -qB3192-