I wanted to understand so I tried to restart the minidlna service and guess what, service would not restart
I added /var/cache/minidlna/ folder with appropriate rights and was able to start the service. But now I don't have any logs in the /var/log/minidlna.log (not a big deal for me, but I can understand the frustration)
I would have thought that when I updated minidlna plugin to 1.0.25 version, the service would have been restarted automatically but it seems it was not the case. Since I did not restart my NAS or changed dlna config, I didn't see that the service could not start properly and wouldn't log anymore.