Although I have no idea what ‘G’ does so I have to look it up…
Okay, yeah, no. You can’t use G. That will send both channels to that independently upon answer. You’re fighting the tools that are provided to achieve what you need to do. Use a pre-dial handler like I mentioned to put the MixMonitor on the dialed channel if you want it. Or put it on the caller before doing Dial(). Or both.
AGI is channel, not call, related.