TCP port forward goes fine but UDP doesn't

[lp]

First of all, I'm using 2.0, but I hope it's a mistake from me and not a bug.

I'm trying to setup a port forwarding. When I setup to redirect TCP port 5070 from WAN to IP1, and then initiate a connection from outside to TCP 5070, I see packets coming to WAN port, then being forwarded on the LAN with proper IP after NATing.
Now it I edit my rule and just replace TCP with UDP, applies, and send traffic on UDP port 5070, I see the incoming packets, but nothing is going outside.

Firewall NAT rule automatic creation is used, and well, it works fine with TCP, so I don't think it's a firewalling issue…

Am I missing or messing something?

Thanks!

[lp]

Forgot to mention that "pfctl -sa" shows:
rdr on re0_vlan3 inet proto udp from any to 88.172.17.14 port = 5070 -> 10.12.3.137

(re0_vlan3 IS my WAN, it's not a mistake)

[lp]

A few builds later, it's now ok…