Not a showstopper, but it's a speedbump when trying to record external devices over USB audio.

The surprising behavior is that the audio from the external device always seems to be routed to USB audio channel 1 and 2 (stereo pair), rather than the pair of channels relevant to the Zone that's externally enabled.

Record a sequence on the Fantom, either using the built-in sequencer or your DAW connected via USB MIDI. Then play the sequence back while recording the USB Audio input in your DAW.

First, configure a Zone in a Scene to control an external device via a particular MIDI channel, but don't use Zone 1. Connect the external device's audio outputs to the line in on the Fantom.