blank white window after maximizing from minimized state

[disconnect]

See the attached screenshot.
It happens frequently, the only solution is to close qbittorrent, which sometimes leads to another problem: phantom qbittorrent process, when there is no window anywhere, but the process still runs.
Also, sometimes the application goes mad, and scans the whole HDD, causing 99% disk utilization.

BTW resuming from minimized state is always needs huge amount of loading from disk, while qbittorrent is installed on an SSD.

Why is this happening? How can i avoid it?