It has been a while since anything has been posted. In that time Audinate has provided online training for Dante audio and video. Highly recommended. https://www.audinate.com/learning/training-certification/dante-certification-program
One of the things that is in the Audinate documentation, but not readily apparent in training is the relationship between Dante packets and multicast ports in switches. This turns out to be the source of the observed problems. I have used virtual devices a great deal, more than others I talk to. I also designed the systems I use so that they are fully supporting multicast. This is great for some of the big shows and complex setups we use, but requires a special setup for virtual devices. In one of the Audinate documents, they specifically mention that IGMP snooping and multicast ports can interrupt virtual device connections. The key is to turn OFF multicast on switch ports you intend to use for virtual devices. Different manufacturers will implement this function in unique ways on their switches, but the secret sauce is that virtual device ports need to pass ALL packets.