My Almond+ stopped accepting new UPnP entries a few days ago, so I did a bit of troubleshooting. Turns out there are a huge amount of duplicate ipfilter entries created by MINIUPNPD. The list is so huge I didn't manage to find out how long it is, but the number is more than 30000 (yes, 30000.) The Almond+ has been up for 19 days.
It goes like this:
Chain MINIUPNPD (1 references)
target prot opt source destination
ACCEPT udp -- anywhere 192.168.1.234 udp dpt:12345
ACCEPT udp -- anywhere 192.168.1.234 udp dpt:12345
....
ACCEPT udp -- anywhere 192.168.1.234 udp dpt:12345
Apparently, the UPnP deamon never checks for duplicate entries when adding new ones into the IP table. Please fix this
Edit: I'm on R072.