Thanks for your reply! But it seems my experience is a bit different. There's no repair failures, everything is downloaded successfully. It's literally just in a "Downloading" status for about 20 seconds, then goes into a "queued" status for 5 seconds, and continues the loop until the download completes.
This will wipe out the queue w/o resetting your settings
sudo docker stop nzbget
rm -rf /opt/appdata/nzbget/queue
ls /opt/appdata/nzbget - check for queue-like files and remove any.
sudo docker start nzbget