SIP ALG turned off, port changes!!!

Hi all.

2 mikrotik routers, connected to each other, lets say R1 — R2

R1(eth1): 192.168.80.1/30 – R2:(eth1): 192.168.80/30, no nat at all
R1 on lan side(eth2): 192.168.85.1/24, several ip phones in 192.168.85.0/24
R2 on lan side(eth2): 10.65.65.1/24, freepbx on 10.65.65.2/24

SIP ALG on both routers is disabled

So there is no masquerade, and static routes exists on both routers to find the opposite lan networks.

Sip phone tries to register on FreePBX, but it registers not with it’s IP, but with the IP of router R2, as it would happen if masquerade was enabled!!!
In R2, with packet sniffer I can see packets coming from sip phones like that:

Src: 192.168.85.44:5060 Dst: 10.65.65.2:5060

but in Freepbx with tcpdump I cannot see ANY packet from 192.168.85.44.

Any ideas?

Show us config of R2 (for starters).