Please provide the following information
libtorrent version (or branch):
platform/architecture: Debian GNU/Linux 9, x86_64
compiler and compiler version:
gcc (Debian 6.3.0-18+deb9u1) 6.3.0 20170516
please describe what symptom you see, what you would expect to see instead and
how to reproduce it.
This issue was originally posted on Reddit r/seedboxes. I am summarizing it here.
Deluge with the 1.1 branch of libtorrent (confirmed on .7, .8, and .9).
Snatching torrents with autodl irssi on IPT and TL trackers.
After seeing the first Announce OK message (not related to the unregistered torrent issue in #315; workaround on that works fine), Deluge connects to only a small fraction of peers. Usually 2 to 5 over confirmed swarms of dozens (also 60+). Often, the uploader does not seem to be included in the swarm, or the uploader is not shown on Deluge because of the bug itself. Download and upload start and performance is (of course) terrible.
There are no other trackers that seem affected by the issue.
Pausing and resuming a torrent mid-race "fixes" the issue. From 2-5 peers, Deluge starts seeing the entire swarm. Most of which are finished already. Download goes to the max, upload is almost none as most of them are at 100% already.
A catch: the issue happens most of the times, but not all the times.
Downgrading to libtorrent 220.127.116.11 fixes the issue completely.
Somebody on Reddit suggested disabling UTP, but it does not solve the issue.