TCP Checksum Empty (not hardware offloading related!) [unresolved]

[pringlescan]

I have pfsense 2.1 beta running in a KVM VM in SmartOS.

HTTP traffic originating from inside pfSense (http health checks) sent to a VM on the same hypervisor/box as pfSense sends empty TCP checksums.

HTTP traffic send to VMs on a different hypervisor/box sends valid checksums.

Traffic originating from other VMs to as well as the hypervisor sends valid checksums and goes through fine.

The only issue is inside of pfSense, there is no trouble in the virtualization or hypervisor, so the problem is somewhere inside of pfSense or how it interacts with the hypervisor.

I have tried using both the virtio drivers and e1000 drivers.

This issue doesn't appear to be related to the beta.

Hardware offloading of any kind is and has been disabled in this exercise.

Any ideas?

TCP Dump, Snoop output and more information available in this post:
http://forum.pfsense.org/index.php/topic,62535.0.html