Midi Key Editor with external instruments?

When I’m in the Key Editor on a midi track for a built , pressing a key on the left of the piano roll view will preview that note. Also selecting or moving a midi note will preview that note.

When the midi track is routed to an Interapp audio Instrument, you don’t hear a preview in the Key Editor. I know the routing works, because if I press play I can hear the midi notes that I’ve recorded. Just no previews.

Is this the expected behavior? I’ve tried it with both Nave and Alchemy.