Audio Mixer plugins offer the illusion of channels.
Why do you say that they offer the illusion of channels - there are channels.
But not channels like you find on analog mixers.
I am fine with that implementation to avoid possible feedbacks.
When you need such a routing then you could use a separate Audio Mixer plugin.
Do you know of some other mixer plugin (there are many on the market) or any other plugin that has multiple audio inputs and outputs where you can route the signal back into it without using a “separate process” e.g. a channel strip, a rackspace, a software loopback device or a hardware driver loopback capabilities?
If you can do this in your DAW - please let us know how you’re doing it without extra channel strips. Maybe we are all missing something obvious?
I suppose I was expecting each subsequent audio mixer (or plugin even) in the chain to act as exactly this kind of separate process, like a separate channel strip. The implication seems to be that GP treats a rackspace as one big channel strip, which leads to the unexpected behavior. The workaround is certainly simple enough, and the Audio Mixer plugins seem lightweight enough that another summing mixer is negligible. It just requires a reframing of how one thinks about what’s going on in the software. Really though, any extra info about why this doesn’t work would be nice, just to have a more intuitive understanding of what I’m working with here. Something about the simultaneity of the audio mixer’s processing threads or some such, I imagine.
An audio mixer in Gig Perofrmer is just another plugin (an effects plugin that can adjust the overall gain of incoming audio just like an EQ plugin might adjust the gain at different frequencies) – it is not a channel strip.
Never dry your dog in the microwave oven… 
Even if you expect a hot dog? 
