Output parameters don't react to voice hierarchy
When you put a simple envelope follower effect on a sound and you turn its fader or the make-up gain all the way down, or you simply mute it, or you change the LP or HP filters to the point where you can't hear the sample anymore, the envelope output parameter keeps sending the same data like nothing has changed.
It seems like the output parameters don't following the same Wwise voice hierarchy as it should send a value affected by all the voice parameters before it gets routed to the Output bus.
@jedsound Do you have multiple voices for the same sfx object in Wwise? In this case it's likely that because each voice is setting the same global RTPC you'll probably see the value for the last voice being processed.
In addition, the make-up gain is in your patch? Or do you mean the volume fader in the Wwise object? I would assume that it's post plugin processing so the patch itself will still be setting the out parameter. And even if the input was silence, the patch will still set the output parameter to 0 (if you're using [env~]).
Can you provide a Wwise project + patch that demonstrates this issue?