HTP Merge engine on MACOS crashing

Trying to setup a process engine to merge three incoming artnet streams unicasted to my mac and then send it out unicasted to one node in the back. The process engine works in forward mode and as soon as I click it into HTP Merge the software hangs and crashes. I've tried doing it over two nics as well but same issue persists. 

I haven't tested the windows/linux build yet to see if it's there. 