Hopefully just a bug, but DaVinci Resolve 18 Public Beta no longer works with Virtual ASIO. It seems to want to try and connect the parent ASIO device instead of connecting to the Virtual ASIO Device selected in its settings page for Video & Audio I/O. I think it's getting confused that because the parent is under exclusive control by the Virtual child, it thinks there's no freely available ASIO ports to connect to and so lists them as 'unnasigned'