Just came back from the Show. I chatted with Matt a bit. Regarding the Dendrobium Burnan's Magic Bean - he agreed it was not registered and it seems to be a made - up name originating in Taiwan. Take it as such!
Now about the dead roots, he immediately pulled out money to reimburse me for the dead root-plants, but I waved him off, thinking/saying that the last growth will hopefully put down new roots. But I pointed out to him to check that new Sphagnum is not wrapped over old Sphagnum which surely will mean dead roots. He agreed.