txg_sync blocked with qbittorrent

System information

Type	Version/Name
Distribution Name	nixos
Distribution Version	25.11
Kernel Version	6.12.65
Architecture	amd64
OpenZFS Version	2.3.5

Describe the problem you're observing

TLDR: When running qbittorrent 5.1.4 the system will freeze due to a txg_sync block. I've noticed this when downloading torrents and re-checking them. I built a new zpool on different drives and tested on both nvme and hdd and the issue persists. Rolling back to kernel version 6.1 and keeping zfs 2.3.5 appears to resolve the issue.

Running a pool scrub doesn't seam to trigger the issue as much, but I think it still happens. Running dd to read or write files doesn't trigger the issue at all.

Zpool status showed no errors. I also let memtest86 run through two passes, no errors. I tried using a HBA card instead of my onboard sata ports and the issue persisted.

I initially thought that my old pool ( a single drive) was dying, so I replaced it with a new pool (4 drives). While restoring my data from backup I didn't encounter this issue at all. It wasn't until my data was restored and I started up qbittorrent that the issue returned. At this point I tried with kernel 6.1 and haven't been able to recreate the issue.

Describe how to reproduce the problem

Include any warning/errors/backtraces from the system logs

I wasn't able to find any logs with any errors relating to this issue.