[Up until a few days ago I was running firmware 1.15 without any problems.]
I have one port that I send all BitTorrent traffic over. Previously, under "Special Applications" I had both the trigger ports and the firewall ports be the same thing. Sometime over the last three days I noticed the hard drives on my DNS-323 weren't spinning as normal. I fired up Transmission on my Mac tonight (which uses the same port) and I see that the port is blocked.
When I setup the port as a Gaming Rule forward to a specific LAN IP there are no issues using the same exact port number. Does anyone have any ideas short of reinstalling firmware? This is a bit of a pain since "Gaming Rules" don't allow the same ports being forwarded to different IPs.