In case anyone else runs into this… My MiniDSP SHD disappeared as a Roon Ready source. Ultimately it turned out that something changed in new Roon version(s) that broke this and I had to go in Settings/Setup to change “Subnet for Linn Streaming” back from the Tailscale subnet to my main subnet. It seems that “Linn Streaming Subnet” = “Primary Discovery Interface” in Roon-speak.