There are several reports in upstream bug tracker ( [1], [2] ) that show the same stacktrace. They both point to a bug in libtorrent-rasterbar 1.1.0 in ip-filtering code, fixed in 1.1.1. so chances are this bug is solved now.
Regards BZ [1] https://github.com/qbittorrent/qBittorrent/issues/5730 [2] https://github.com/qbittorrent/qBittorrent/issues/5428
