Hi,
When you open the VCA 2 (and also VCA 1 is open), then you open the gate so sound will pass without triggering voices.
This can ie be useful for making drones.
I suggest you read about the VCA section in the manual for more informations about this.
Also keep in mind that the behavior you exsperience also will depend on the settings you have on the Voices page to handle voices. That include the STEAL settings.