I talked about this with the libtorrent author yesterday and he told me that it might be caused by invalid tracker URLs. He said that there are still some tracker announcing issues in v0.15.3 that he is hoping to fix for v0.15.4.
An easy way to test it he said would be to create a torrent with an invalid tracker URL (for example not starting by http://) and load it.
I talked about this with the libtorrent author yesterday and he told me that it might be caused by invalid tracker URLs. He said that there are still some tracker announcing issues in v0.15.3 that he is hoping to fix for v0.15.4.
An easy way to test it he said would be to create a torrent with an invalid tracker URL (for example not starting by http://) and load it.