We both use a 50S for speaking together. When paired with bluetooth and HD Audio we always perfectly hear each other.
As soon as we pair with mesh (group mesh) in order to listen to music together, only every 3rd time or so the voice is transmitted.
It goes so far, that mesh is unusable for us as we cannot hold a conversation together, due to the fact that the voice is not transmitted.
Same problem even with music off and only mesh. The second we deactivate mesh and activate bluetooth - everything works perfectly fine!
But that is not what I want and expect from such a high priced product.