That’s correct but the solution is unfortunately not straight forward as changing that block of code has significant consequences. There are multiple solutions, each with benefits/drawbacks which I am currently investigating.
I have posted a fix for the NAT issue, you can download the latest source from here https://bitbucket.org/MarcF/networkcomms.net/get/tip.zip. I have briefly tested the fix but if you could download and confirm that would be appreciated. Assuming there are no further problems this fix will be in the next version release.