nova2.py search engine process keeps running and listening after i close qbittorrent

[milahu]

qBittorrent & operating system versions

qBittorrent: 4.6.5 (64-bit)
Qt: 6.7.2
Libtorrent: 2.0.10.0
Boost: 1.81.0
OpenSSL: 3.0.14
zlib: 1.3.1
Operating system: NixOS Linux

What is the problem?

my old qbittorrent instances were listening on ports 6881, 6882, 6884

problem: old nova2.py processes are still running, still listening on ports 6881, 6882, 6884

expected: on exit, qbittorrent should kill all child processes

$ ps -AF | grep -E $(netstat -lntup 2>/dev/null | grep -E ':688[124]' | cut -c78- | cut -d/ -f1 | sort -u | xargs printf '|%s' | tail -c+2) | grep -v 'grep -E'
user     2387833    2171  0  9131 19504  11 Sep21 ?        00:00:01 /nix/store/pgb120fb7srbh418v4i2a70aq1w9dawd-python3-3.12.5/bin/python3 -I /home/user/.local/share/qBittorrent/nova3/nova2.py jackett,snowfl,solidtorrents all some query 1
user     2474568    2171  0  9132 19516  10 Sep22 ?        00:00:00 /nix/store/pgb120fb7srbh418v4i2a70aq1w9dawd-python3-3.12.5/bin/python3 -I /home/user/.local/share/qBittorrent/nova3/nova2.py jackett,snowfl,solidtorrents all some query 2
user     2561974    2171  0  9125 19344   9 Sep23 pts/25   00:00:00 /nix/store/pgb120fb7srbh418v4i2a70aq1w9dawd-python3-3.12.5/bin/python3 -I /home/user/.local/share/qBittorrent/nova3/nova2.py snowfl,jackett,solidtorrents all some query 3
user     2570424    2171  0  9116 19448   5 Sep23 pts/25   00:00:00 /nix/store/pgb120fb7srbh418v4i2a70aq1w9dawd-python3-3.12.5/bin/python3 -I /home/user/.local/share/qBittorrent/nova3/nova2.py snowfl,jackett,solidtorrents all some query 4

workaround: kill old nova2.py procs manually

netstat -lntup 2>/dev/null | grep -E ':688[124]' | cut -c78- | cut -d/ -f1 | sort -u | xargs kill

my current qbittorrent instance is listening on port 6883

$ ps -AF | grep -E $(netstat -lntup 2>/dev/null | grep -E ':6883' | cut -c78- | cut -d/ -f1 | sort -u | xargs printf '|%s' | tail -c+2) | grep -v 'grep -E'
user     2686718    2171 42 76614680 10774760 3 10:31 ?    00:23:27 /nix/store/zx7l7p2jg0nsqc38n293ldll23z2rnlg-qbittorrent-4.6.5/bin/qbittorrent

Steps to reproduce

not clear

maybe the search engine (nova2.py) crashed
because i closed the search tab too early

Additional context

No response

Log(s) & preferences file(s)

No response