Sounds like your issue is with your Windows VM. Which virtual adapter are you using and do you have vmware tools installed?
Maybe. That's what I thought. But smb is fine going from one windows VM to another (even when one of them has the drive hosted in FreeNAS). Its only SMB from windows to FreeNAS thats borked. All of the virtual adapters are vmxnet3 and tools are installed. There are only 2 vswitches - one is management with physical NICs, the other doesnt have any NICs and only does storage traffic between VMs. MTU settings have nothing to do with it and I even tried deleting all of the networking and set it up with E1000E adapters.