All the Polyend MIDI class-compliant instruments, besides sending the MIDI data, is also transmitting - CDC (serial) and Raw HID. Seems like for some reason iConnectivity gear cannot filter these, while most of the hubs we're using are doing this without any issues. They are aware of this and maybe one day they'll get kind enough to implement filtering of these messages in their gear. We'll see. Before this happens we consider our instruments as incompatible.