Firewall/NAT

We're experiencing an issue with inbound NAT of RTP traffic (UDP 10000 - 10051). 

Here's the NAT rule:
<rule>
            <protocol>udp</protocol>
            <external-port>10000-10051</external-port>
            <target>192.168.0.12</target>
            <local-port>10000</local-port>
            <interface>wan</interface>
            <descr>RTP</descr>
</rule>

Here is what is logged in status.php:
Sep 13 22:18:01 m0n0wall ipmon[122]: 22:18:00.793775 bge0 @200:1 b 209.XXX.XXX.60,17375 -> 192.168.0.12,10025 PR udp len 20 116 IN bad NAT
Sep 13 22:18:01 m0n0wall ipmon[122]: 22:18:00.811888 22x bge0 @200:1 b 209.XXX.XXX.60,17374 -> 192.168.0.12,10024 PR udp len 20 200 IN bad NAT

I've tried a different physical NIC,  turning on allowance of fragmented packets and the most basic configuration possible.

Does anyone have any suggestions or could someone even just confirm if they have a m0n0 config working with inbound NAT of RTP?

This issue exists in version 1.32 as well as 1.3.  I tried testing in 1.236 but the boot process will not complete successfully in my test system (Dell PowerEdge SC430).