Does it work on LAN or WAN or broke on both?
What port (LAN or WAN) are you doing the tcpdump?
It sounds like they are getting into the router (rule stat counter) so do a tcpdump on the LAN port and see if they are exiting there. If not is there a firewall in play here?
If the packets are getting on the router but not on the LAN, ping the destination (LAN) ip from the router. If it is not reachable then something is dropping them on the router. If it is reachable but the packets are not getting on the LAN it's likely a firewall rule, unless there is none?
Someone will eventually ask so I'll do it now. More info would help a lot. :-)