I was just going to say the same thing. My workaround, for which I can't
even give complete instructions, is not a solution. Nor does it solve
the issue where the Chromecast is seemingly factory resetting an
independent device and removing it from it...
I had a ghost soundbar at one point, but I was finally able to work
around and get it removed. Forgive me, I forget exactly how as it was
late and I'd hit the frustration point of mashing buttons to try and get
it fixed. I may have added it to a diff...