I feel like this may have been covered before, but...
I've got a bass sound being sequenced on Pad B16. I am sending that same sequence out to an external MIDI synth. When I turn the volume of the internal sound down to zero (this applies to both volume controls, on the Fdbk/VCA and Mixer screens), it stops the sequence to the external MIDI device and the pad light no longer flashes to show sequencer action. I feel like this is really unintuitive. It's like it engages the mute function, but really, it should only be working with volume mix levels. I assume this is meant to help with voice allocation, but it is not expected user behavior.