Jails preventing SMART short self-test from completing

[mathhov]

My main pool is built with 6x WD60EFRX.
SMART self-test used to work, but now, it's not anymore.
I've got all these jails named with the corresponding software:
Jackett
Organizr
Plex
Radarr
ReverseProxy (Caddy and NGINX)
SickChill
Sonarr
Tautulli
Transmission
Transmission_VPN

Somehow, SMART tests, whatever if its a short or a long get stays stuck at "10% remaining".
Stopping all my jails instantly allows them to end.

If I start these back, maybe a short-test will go through but not more than that. (I'm doing 3 short self-test a day and 1 long each month).

I'm sure that I must not be the only one in this situation.
What's wrong with my setup?
Can someone pinpoint what jail/jails could prevent my SMART tests from completing.
Thanks in advance,

 

[mathhov]

Well, it look like my two Transmission jails are to blame. It turned out that I just had to stop these two jail to allow the self-test to complete. Why? Can I modify something to prevent this? Even with no active torrent, I still have this issue.