I found some upstream issues (#6422, #6555) about a similar crash on different 3.3.x versions and they all point to an immature support of libtorrent-rasterbar 1.1.x series. The current qbittorrent version (4.4.1) is built with libtorrent-rasterbar 1.2.x so it seems safe to close this bug report.
Regards BZ
