If this is the origin of this issue, the HDMI management, it surely should be reported to the origin, whatever it is, either vuplus itself or OpenViX coders. Because, this might seem a minor issue, but in my opinion it's not because, it often happens to have events you want to listen from a channel and view from another one.
And this is not just because of encryption! For instance, I like ski, and it is broadcast by our RaiSport+HD, but the quality of this channel is not at the same level of Swiss ones, where they have a much higher bitrate.
So, I could (before OBH 4.1.030, as I explained) and I still can do in my dad's Duo2, watch these events from RSI La2 and listen from RaiSport+HD. Or similar examples.