Yes, I always reset to defaults after every major release. I did find out something interesting. 45 minutes after closing my torrent client, there are still 9.8k connections open. The vast majority of those all have the same status:
root@OpenWrt:~# cat /proc/net/nf_conntrack | grep -i assured | grep -i established | wc -l
9714
Does this fact help in any way? I am not entirely sure what "ASSURED" means in this context.